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Geological Survey of Michigan. 

Vol. IX Part II Plate I. 



m ■ 























Entered according to Act of Congress in tbe year 1904, by 

-Governor a. T. Bliss 

for the State of Michigan, in the Office of the Librarian of Congress, Washington, D. C. 

Office of the State Geological Survey, 
Lansing, Mich., July 26, 1903. 

To the Honorable, the Board of Geological Survey of Michigan: 

Hon. A. T. Bliss, Governor and President of the Board. 
Hon. L. L. Wright, President of the Board of Bducaiion. 
Hon. Delos Fall, Superintendent of Public Lis! ruction and Sec- 
retary of the Board, 

Gentlemen: — Herewith I transmit as Part II, the concluding part of 
Vol. IX, a report containing the results of examinations and teste by G. P. 
Grimsley, of the gypsum resources of the State so far as they are at present 
developed. It also includes especial notes by W. M. Gregory on the ala- 
baster area and some account of the general state of the industry, which 
Mr. Grimsley wishes to include at no extra expense to us. 
With great respect, I am, your obedient servant, 


State Geologist . 



Prefatory, General 1 



Sec. 1. MIneralogtcal Properties of Gypsum 3 

Solubility of Gypsum 4 

2. Early History *. 5 

3. Consolidation of Gypsum Companies 7 

4. Brief Summary of the Report 8 


Gypsum in Other Countries and States. 

1. Gypsum in England 11 

2. Australia. 12 

3. India 12 

4. Tasmania 14 

ft. Canada 14 

6. Cyprus 15 

7. France 16 

Methods of Calcining, Improved Types of Kilns 16 

8. Germany 20 

Mode of Calcining 20 

9. Switzerland 22 

10. Sweden 22 

11. Italy 22 

Gypsum in the United States. 

i 12. General Remarks 23 

13. Gypsum in New York 23 

Fayetteville. Cayuga Plaster Co. 
Wheatland Land Plaster Co. 
Oaklleld Gypsum Deposits. 

14. Ohio 25 

15. Pennsylvania 26 

16. Virginia 26 

17. Iowa 27 

18. Kansas 28 

19. Arkansas 29 

2D. Oklahoma 29 

21. Texas 30 

22. Colorado 31 

23. Wyoming 32 

24. Nevada 33 

Lovelock Deposit. 

25. California 34 

26. Other Districts 86 


Secondary Gypsum Deposits. Page. 

27. Earthy Gypsum, Distribution of 80 

28. In Kansas 87 

29. In Oklahoma and Indian Territory 87 

80. In Texas. 38 

81. In Wyoming 88 

82. Microscopical Examination of Gypsum Eartb 80 

88. Chemistry of Gypsum Earth 89 

34. Origin of Gypsum Earth Deposit 40 

Spring Theory of Origin 41 


History or the Gypsum Industry. 

1. Early Reports of Michigan Gypsum 42 

2. History of Grand Rapids District, South of the River 48 

3. History of Grand Rapids District, North of the River 47 

4. History of the Grandville District 49 

5.« History of the Alabaster Deposits 60 


Geology and Topography of Michigan Series Gypsum. 

1. Geological Section 62 

2. Geological History of the Michigan Basin 64 

3. Michigan Group of Rooks 60 

4. Glacial Geology of the Grand Rapids area 66 

6. Topography of the Grand Rapids area 69 

6. The Alabaster Area, by W . M. Gregory 60 

7. Paleozoic, Geological Formations of, by VV. M. Gregory 66 

8. Huron County, L 77 


Gypsum Deposits of St. Ignace. 

1. Historical 80 

2. St. Ignace Wells 81 

3. Rabbit's Back 82 

4. St. Martin's Island, etc 88 

A Study of Well Borings. 

1. Preliminary 84 

2. Carboniferous (Grand Rapids Group) Gypsum 81 

8. Well Records Near Grand Rapids 92 

4. Drillings by Pittsburg Plate Glass Company 96 

6. Gypsum in the Wells Reaching the Silurian 97 

6. Conclusion 97 

7. Total Quantity of Available Gypsum in Michigan 98 


Michigan Mines and Mills. 

1. Grand Rapids District 99 

The Alabastine Company 99 

The Alabastine Mill 102 

The Godfrey Mine and Mill 104 



The Powers Mine and Mill 10ft 

The Grand Rapids Plaster Company's Mines and Mills 107 

The English Mill and Mine 108 

2. G ran dville Area .* 109 

The Durr Mine and Mill 110 

The White Mill Ill 

3. Alabaster , Ill 

Other Gypsum Deposits In the Alabaster District 113 


Technology of Gypsum and the Gypsum Plasters. 

1. General Process of Manufacture lis 

2. Crushing of the Rock 116 

3. Calcining 119 

4. Cummer Rotary Calciner 136 

5. Progress in Technology 130 

6. Use of Retarders 133 

7. The Set of Plaster 135 

Lavoisier Theory. 
Landrin Theory. 
Ch atelier Theory. 
Grimsley Theory. 


Chemistry oip Gypsum and Gypsum Plasters. 

1. Composition 140 

2. Payen's Experiments HI 

3. Chatelier's Experiments 141 

4. Chemistry of Foreign Gypsum 148 

5. Canadian Gypsum 144 

«. United States Gypsum 144 

Ohio. Florida, low iv Kansas 145 

Kunsas Gypsum Earth, Oklahoma. Indian Territory. T*xas 

Gypsum Earth. Colorado and Wyoming, California 146 

7. Chemistry of Michigan Gypsum 147 

Method of Sampling 148 

Method of Analysis 149 

Michigan Gypsum Analyses. 

Western Michigan 150 

Alabaster 153 

St. Ignace 153 

Anhydrite Analysis 155 

8. Chemistry of the Finished Plasters 155 

Plaster of Paris in France. 

Ohio Plaster, Wyoming Plaster, Kansas Cement Plaster 150 

Texas and Oklahoma Plaster 157 

Michigan Plaster 158 


1. Introduction 161 

2. Fineness 162 

3. Weight 162 

4. Gauging of Plaster 163 

5. Time of Setting 163 

6. Tensile Strength 165 



Appliances 165 

Mixing Ifl0 

Breaking 167 

Tables 168 

Discussion of Results 170 

Tests on Old Plasters 172 

Some Low Tests 178 

7. Comparison of Physical Tests with Chemic til Analyses 174 

8. Compression Tests 176 

P. Absorption Tests and Effect on Strength v ? 176 

10. Tensile Strength of Gypsum and Lime Plasters 177 

11. Adhesion Tests 178 

12. Specific Gravity 179 

13. Influence of Sand on Plaster 181 


Origin of Gypsum. 

1. Deposition by Action of Sulphur Springs and Volcanic Agencies 182 

2. Hunt's Chemical Theory 188 

3. Deposition Through Action of Pyrites on Lime Carbonate 184 

4. Gypsum Deposited in Rivers 184 

5. Secretion by Animals 184 

6. Gypsum Formed from Anhydrite 185 

7. Gypsum Deposited from Sea Water. 185 

8. Mediterranean Sea 187 

9. Michigan Carboniferous Salt Sea 187 

10. Caspian Sea 188 

11. Michigan Caspian Sea 188 

12. Vein Deposition 191 


Gypsum as a Fertilizer. 

1. Early Experiments 192 

2. Early Use in America 198 

Grece's American Experiments 193 

Ruffin's Experiments 193 

Harris' Experiments. 193 

3. Theory of DeCandolle and Chaptul 197 

4. Gypsum as Direct Plant Food 198 

5. Retention of Ammonia by Gypsum 198 

Stockhardt'8 Theory. 

6. Van Wormer's Experiments 199 

7. Boussingault's Experiments 2v0 

8. Davy's Theory 201 

9. Recent Theory of Storer 201 

10. Experiments in Kansas. 202 


The Uses of Gypsum. 

§1. Uncalcined Gypsum 204 

Terra Alba, Manufacture of Crayons, Hardening of Gypsum Blocks, Use in 
Portland Cement 205-206 

2. Calcined Gypsum 208 

3. WallPlasters 208 

Gypstone 212 

4. Manufacture of Hardened Plasters 213 

ft. Gypsum Paints 216 

6. Selenitic Lime 216 



7. Alabastine 217 

8. Lieno 217 

9. Trlppolite 216 

10. Pottery Moulds 218 

11. Plate Glass Polishing 219 

12. Plaster Relief Work 219 

13. Manufacture of Floor Blocks 220 

14. As a Basis of Portland Cement with Sulphuric Acid as a By -Product 222 

Appendix a. 

Statistics of Gypsum 224 


Bibliography on Localities and General Properties of Gypsum 232 

Index 243 





1. Form of Gypsum Crystal 4 

2. Common Form of Gypsum Crystal 4 

8. Twinned Gypsum Crystal 4 

4. Twinned Gypsum Crystal, with rounded edges 4 

5. (a) Common Type of French Gypsum Kiln 19 

(b) Dumesnil Gypsum Kiln Used in France 10 

6. German Plaster Kiln 21 

7. Geological Section of Wyoming Gypsum Deposits 32 

8. Cross-section of the Lower Michigan Basin 52 

9. Correlation of Rocks Miss. Valley and Michigan 55 

10. Geological Section of Huron county 79 

11. (a) Section A 1 abas tine Quarry 99 

11. (b) Section Alabastine Quarry Showing Uses 99 

IS. Section Godf rey Quarry 104 

13. Section at Taylor Brick Yard 104 

14. Section at Powers Shaft Nine 105 

15. Section Grand Rapids Plaster Co. Miue 105 

16. Section Durr Mine 105 

17. Day's Lightning Plaster Mixer 108 

18. Jaw Crusher for Grinding Gypsum 115 

19. Gypsum Disintegrator. (Closed) 116 

20. Gypsum Disintegrator. (Open) 117 

21. Sturtevant Emery Mill 118 

22. Siunevant Emery Mill Stone 119 

23. Day Fiber Picker 119 

21. Ehrsani Calcining Kettle 120 

25. General Plan of Plaster Mill 121 

26. Four Flue Gypsum Calcining Kettle 122 

27. Cummer Continuous Calcining Kettle. (Sectional view) 126 

28. Cummer Continuous Calcining Kettle. (Outer view) 127 

29. Cummer Continuous Calcining Kettle. (End elevation) 128 

30. Broughton Plaster Mixer 130 

31. Uncalclncd Gypsum Earth X 500 137 

32. Calcined Gypsum Earth & Hour After Water Was Added to it x COO 137 

33. Gypsum Crystallized from Solution in Water after Standing Three Days \500 13* 

34. Uncalcincd Ground Gypsum in Water, after Standing Three Days x 600 138 

35. Calcined Gypsum Earth from Central Kansas x 500 1 <9 

36. 37, 38, 39. Various Forms of Cement Briquette ahd Clip KM 

40. Fairbanks Cement Testing Machine 167 

41. Chart of Tensile Strengths of Gypsum Plasters 171 

42. Testing Apparatus. it<o 

43. Lime Stone Altered in Part to Gypsum. (From Dana) 183 

44. Metal Lath Used in Plaster Work 210 

45. Gypsum Floor Blocks 220 

46. Gypsum Boards 221 

« 7 - | I 22 < 

48. VGypsum Statistics J 225 

49. » > -.*26 



I. Early Plaster Men in Michigan Frontispiece. 

II. A. Plaster Creek and Alabastine Mill 8 

B. Mining Gypsum 8 

III. Map of Grand. Rapids Area 16 

IV. Map of Alabaster Area 24 

V. Alabastine Gypsum Quarry near Grand Rapids 32 

VI. Alabastine Mill at Grand Rapids 48 

VII. Alabaster Gypsum Quarry, showing boulder clay 56 

VIII. Alabaster Gypsum Quarry, showing gypsum ledge 64 

IX. Alabaster Gypsum Quarry, dock 72 

X. A. Car coming out of Mine 80 

B. Mushrooms In Gypsum Mines 80 

XI. Mules in Gypsum Mines 88 

XII. A. Durr Gypsum Mill at Grandville 96 

B. Gypsum Quarry of Durr Mill at Grandville 96 

XIII. Old Red Gypsum Mill at Grandville 104 

XIV. White Gypsum Mill at Grandville, as seen from quarry 112 

XV. Grand Rapids Plaster Co. Gypsum Mine, entrance to 120 

XVI. Map of Michigan Showing Location of Wells 128 

XVII. Map of Land Controlled by the Pittsburg Plate Glass Co. at Grand Rapids 136 

XVIII. Buhr Stone Mills Grinding Gypsum; Grand Rapids Plaster Co 144 

XIX. Top of Gypsum Kettles in Mill of Grand Rapids Plaster Co., at Grand Rapids 152 

XX. Mill(No. 1.) of the Grand Rapids Plaster Co 160 

XXI. Sketch Map of the St. Ignace Area 168 

XXII. A. Old Lime Kilns on slope of Rabbit's Back 176 

B. Rabbit's Back Ridge, St. Ignace 184 

XXIII. Cement Plaster Mill and Gypsum Earth Deposit of Acme Cement Plaster Co., 

Kansas 192 

XXIV. Plan of Modern Gypsum Mill erected in Kansas 200 

XXV. Alabastine Wall Tints : 208 

XXVI. Chicago Plant of the Alabaster Company 216 

XXVII. Lieno Wall Decorations (IT. S. Gypsum Co.) 224 

XXVIIL Lieno Wall Decorations (U. S. Gypsum Co.) 232 

XXIX. Index M<ip of the U. S. with Gypsum Fields located End 


Page 23, line 7, refer to Plate XXIX instead XIII. 

Pages 47, 50, and index, Mr. Church's initials are M. V., not M. B. 

Page 76, line 16, read Pinconning for Bay City. Also, the Detroit and Mackinac 
R. R. is thus spelled with a terminal c, while the division of the M. C. R. R. is 
spelled Mackinaw. 


The writer of the following report was first interested in the study of 
gypsum and hard wall plasters, when he became a member of the Uni- 
versity Geological Survey of Kansas in 18MJ. Three years were spent 
in a careful study of the Kansas deposits and of the methods of manu- 
facture of wall plasters. This study was carried on in the field, library, 
and laboratory. The results of this work were published in Volume V 
of the Kansas Survey reports. 

Since that time the gypsum deposits in Oklahoma, California, and 
Ohio have been investigated; and in the laboratory many experiments 
have been tried on calcining and mixing various materials with gypsum, 
and in physical tests on the plasters and mixtures. 

In the summer of 1002, on the invitation of Mr. Alfred C. Lane, State 
Geologist of Michigan, I spent nearly two months in the field on a study 
of Michigan gypsum. This work has been followed by careful chemical 
and physical tests and by a search of American and European litera- 
ture for additional information. 

In collecting the accounts of the gypsum industry from abroad and 
from this country. I wish to express my obligation to the scientists who 
have so kindly sent me data and references. These persons are men- 
tioned by name in ihe chapters devoted to these subjects. 

In my Michigan work I wish to express my appreciation of the favors 
extended to me by the State Geologist, Mr. Lane, who has placed in 
my hands, records, books, and notes, relating to the subject in hand, 
and who has in other ways aided me in this investigation. 

I am indebted to Mr. Frank Leverett for the account of glacial geology 
of the Grand Rapids area, and to the report of Mr. W. M. Gregory for 
the geology of the Alabaster district. J am especially indebted to the 
officers of the various gypsum companies who have extended to me 
every courtesy and have cheerfully furnished me with desired informa- 
tion about their mines and mills. Without this co-operation this report 
would have been of little value. 

The officers of the U. S. Gypsum Company have placed in my hands 
samples of their products for physical and chemical examination, and 
have furnished me with information about the development and history 
of the Michigan gypsum industry before and since the time they secured 


so large a control. Most of the localities studied are reached by the 
Pere Marquette railroad, aud I wish to return my thanks to Mr. S. T. 
Crapo, General Manager, for favors extended to me in this work. 

Many of the men prominent in the early history of the gypsum in- 
dustry in Michigan, have passed away aud others have advanced in 
age. The effort was made to secure and record the information about 
the early history as nearly first hand as possible. In a short time this 
would have been impossible, and some of these men have died since this 
work was started. 

It is hoped that this volume may be of some service to the gypsum 
development in this Slate, and Michigan is to be congratulated on the 
history and development of this plaster industry. It will continue to 
develop in the future. 

Topeka. Kansas, June, 11)03. 



§ 1. Mineralogical Properties of Gypsum. 

Gypsum is a mineral composed of sulphate of lime aud water, with 
the chemical formula CaS0 4 + 2H 2 0. It is one of the softest minerals 
and in the old Mobs' scale of hardness it stands number 2 in the scale 
of 10. It has a specific gravity of 2.32, i. e: w e ighs abou t-^. 320 o unc e s - 
t^ the mbio foot , 

The specific gravity of gypsum is shown in comparison with lime- 
stone, cement, etc., in the following table taken from Mr. Wilder's re- 
port r 1 

Limestone 2.46 to 2.84 

Quicklime 2.30 to 3.18 

Lime mortar 1.04 to 1.86 

Gypsum • 2.30 to 2.40 

Calcined gypsum 1.81 

Portland cement 2.72 to 3.05 

Anhydrite 2.89 to 2.98 

I have no data on specific gravity of the set plaster, but I believe it. 
will be nearly the same as the gypsum rock. 1 tried to determine the 
expansion in setting or the relation of dry plaster to the set plaster, in 
volume. I could detect no expansion by direct measurement and by 
filling a thin glass bottle with mixed plaster and permitting it to set 
in this case the bottle w r as not broken or cracked. I could not run in 
a colored liquid around the plaster so apparently it did not shrink/ 

Gypsum crystallizes in the monoclinic crystal system in the form of 
plates or prisms with pyramidal terminations. The relative lengths of 
the crystal axes are represented by the formula 0.6891:1:0.4156, while 
the angle of the inclined axis to the vertical is 81° 5'. Twin or united 
crystals, as shown in Figure 3, are very common, where the crystals are 
twinned on the orthopinacoidal face. 

'Iowa GeoL Survey. Vol. XII. p. 139; 1901. 
*But see Chapter XI, ifi. 



Pig. 1. 
Fig ures 1 to 4 : 

Fig. 2. 

Fig. 3. 

Fig. 4. 

1 . One form of gypsum crystal. 

2. Common form of gypsum crystal. 
*. Twinned gypsum crystal. 

4. Twinned gypsum crystal with rounded edges. 

The typical forms of the crystals are shown in Figures 1 and 2. The 
cleavage is almost perfect on the face 5, which explains the plate-like 
characters of gypsum found in the rocks. Cleavage very often takes place 
on the face n cutting across the first cleavage. The faces of the twin 
crystals are sometimes rounded as shown in Figure 4. This is especially 
characteristic of the many crystals near Mont-martre near Paris, so 
such crystals are sometimes called Mont-martre twins. Perfect gypsum 
crystals are rather rare in Michigan rocks. 

Mr. A. M. Apted of Grand Rapids has an extensive collection of Mich- 
igan gypsum crystals at his house. "White flint seams'' stand >n relief on 
weathering. The flakes of selenite sometimes cover as much as one inch 
on the gypsum. The veins of salt are about one-fourth inch thick. He has 
a fine specimen of calcite crystal with gypsum from Hope, Kansas. This 
gypsum is very hard and fine grained. The Deadwood gypsum is fine 
grained. The Fort Dodge gypsum is coarse and has marked characteristic 
brown and white lead. The Sandusky gypsum is fine grained and flinty. 
Some specimens show a red gypsum with white combs of gypsum crystals 
between, but there is a fine gypsum crystal standing alone with a peculiar 
kink showing the flexibility of the same. 

There are two types of crystals; one prismatic in. b, with oblique termi- 
nation as illustrated, and others with nearly square ends, and this face 
nearly perpendicular to the prism (e) has a much duller lustre. There is 
one specimen of gypsum with geode cavities of crystals in the middle but 
this is said to be rare. From Syracuse, N. Y. we have red gypsum crystals. 

Solubility of Gypsum. 

(ivpsum is only slightly soluble in water, as shown in the following 
table of Marignac i 1 

i Annales de Cbimie. Paris. 5th series, vol. 1. pp. 274 to 281, quoted by Chatard, Seventh Annual U. 
S. GeoL Survey, and verified by the writer. 



At 32° F.- 0°C 

At G4.5° P.- 18°C 

At 75.2° F.- 24° C 

At 89.6° F. - 32° U 

At 100.4° F.- 38° C 

At 105.8° F.~ 41° C 

At 127.4° F.- 63° C 

At 161.6° F.- 72° C 

A 1 186.8° F. - 80° C 

At 212 °F.-100° C 

One part gypsum 
dissolves In— 

415 parts of water 





370 " 





One part anhydrous 
sulphate lime dis- 
solves In— 

525 parts of water 




466 •• 

468 • 


495 •* 

5*8 - 


The maximum solubility is fouud at 38° C. or 100° F., and then only 
one part of gypsum dissolves in 368 parts of water, while about 40 parts 
of common salt will dissolve in 100 parts of water at a temepralure of 60° 

§ 2. Early History. 

Gypsum has been used in various ways from very early times. On ac- 
count of the soft lustre given to the light as it is passed through the 
transparent plates of gypsum, the ancient people were reminded of the 
light from the moon, and so named this variety of gypsum selenite from 
a Greek word o-cXi/ny = the moon. Selenite was regarded by these 
people as the most delicate variety of alabaster and was used by the 
wealthy in their palaces as windows. 

The walls of the old temple of Fortuna Seia 1 were constructed of stone 
supposed to be compact gypsum and * % the interior though without^ win- 
dows was rendered sufficiently light by rays transmitted through its 
semi-pellucid walls." 

At Florence the gypsum of Volterra was made into vases in which 
lamps were placed, throwing a soft light over the room. In Arabia the 
building of Arsoffa Emii, supposed to be an old monastery, is constructed 
of gypsum, "and when the sun shines on it, the walls give such a lustre 
that they dazzle the eyes, but the softness of the stone and redness of the 
mortar have conspired to make it a very ruinous pile at present, though 
of no great antiquity; the stone having split and mouldered away in the 
wall and the foundation has failed in many places." (Kees in 1814.) 

The writings of Theophrastus and Pliny show that the Greeks were 
familiar with the uses of plaster, made by calcining the gypsum stone, 
in making casts. They state that the first plaster casts were made by 
Lysistratus of Sicyon, who was a brother of the famous sculptor Lysip- 
pus. He made first a cast in plaster from the object and from this 
obtained a second one in wax. Rhaecas and Theodorus of Samos worked 
by the same method, but the art appears to have attracted very little at- 
tention and was soon neglected and in course of time forgotten. It was 
revived by Verocchio (1422-1488) and others, when the method of casting 

L , Rees' Cyclopedia of Arts, Sciences, and Literature: 1814. 


in plaster proved of great service in obtaining copies of the specimens of 
ancient sculpture which were then discovered. 

The compact variety of gypsum, or alabaster, is frequently referred 
to in ancient writings; though this word is so often used to describe the 
stalactitic carbonate of lime, that it is not possible to tell from the 
meagre descriptions whether the alabaster mentioned is the sulphate or 
carbonate of lime. 

The derivation of the word is a much disputed question. According 
to some writers it is derived from two Greek words, a = without, and 
Xa/&u = handles, referring to a box without handles made from this 
material and used to hold perfume. This derivation is said to be in- 
consistent with the rules of formation of the Greek language, and the 
derivation was probably given long after the word itself was coined. A 
similar derivation, more consistent with the Greek rules, gives an 
origin based on physical character, from a, = not and \afi /3dv<o (Latin 
Capio) = to take, so named because the rock is smooth and slippery 
and difficult to handle. Another writer gives an Arabic origin, from 
al batstratron, meaning a white stone. A derivation which seems more 
probable connects the word with the town Alabastron, in Egypt, where 
in early times there was a manufactory of urns, vases, and other orna- 
ments made from the gypsum stone found in the mountains near by. 

The alabaster used in these* early days came mainly from Syria and 
upper Egypt. The statues and basso relievos of the mausoleum of the 
Connetable de Lesdiguieres, of the cathedral of Gap, were made of ala- 
baster taken from Boscadon near Embruii, in the High Alps. The 
Encyclopedia Perthensis, written in 181G. states that: 

"There is a church in Florence still illuminated, instead of by panes 
of glass, by slabs of alabaster near fifteen feet high each of which forms 
a single window through which light is conveyed.*' 

Gypsum rock was not very thoroughly examined or investigated until 
the last century. Chambers' Dictionary of Arts and Sciences in 1753 
gives the following summary of the knowledge concerning this mineral 
down to that time: 

"Gypsum in natural history, the name of a class of minerals, the 
characters of which are these: They are composed of small flat particles 
irregularly arranged, and giving the whole mass something of the ap- 
pearance of the softer marbles; they are bright, glassy, and in a small 
degree transparent ; not flexible nor elastic, nor giving fire with steel, 
nor fermenting with or dissoluble in acid menstruum, and calcine very 
readily in the fire. Of this class of bodies there are two orders. The first 
order is of gypsums which are of a firm, compact texture and consider- 
ably hard. The second, of those which are of a lax or loose texture and 
are accordingly soft and crumbly.'' 


§ 3. Consolidation of Gypsum Companies. 

The gypsum industry has shown a marked increase in recent years 
in the United States. In 1902 the total production was $16,478 tons, 
with a value of $2,089,341 according to the U. S. Geological Survey. 
Michigan holds first rank among the states in the total amount of gypsum 
quarried, and probably first ranjc in value at the present time. 

Consolidation seems to be the order of the age, and the gypsum in- 
dustry has proved no exception to the rule. When it was announced 
in 1901 that a two million dollar trust was being organized to control 
the gypsum industry, many people for the first time began to wonder 
what the gypsum industry really was; but very little serious considera- 
tion was given to the announcement of consolidation. 

On February 1st, 1902, the United States Gypsum Company was in- 
corporated with Mr. B. W. McCausland, president; O. B. English, vice 
president; Emil Durr, treasurer; with a capitalization of $7,500,000. 
These men were already well known plaster men in Michigan. Mr, Mc- 
Causland had been president of the Alabaster company, Mr. Durr was 
associated with the Grandville mill, Mr. English had built a new T and 
modern mill at Grand Rapids. 

This company soon obtained control of eighteen plaster mills, thirteen 
mixing plants, and three chemical mills distributed as follows: Three 
mills in Michigan, two mills and two mixing plants in Ohio, one mixing 
plant in Pennsylvania, two mills and two mixing plants in New York, 
one mixing plant in Indiana, one mill and two mixing plants with two 
chemical mills in Illinois, two mixing plants in Wisconsin, two mixing 
plants and one chemical mill in Minnesota, six plaster mills in Iowa, one 
mixing plant and a retarder factory in Nebraska, three plaster mills in 
Kansas, and one mill in Oklahoma. This company has its main otlices in 
Chicago and branch otlices in eight other leading cities. 

In the historical sketch which follows, the attempt has been made to 
show the development of the plaster industry in the State, from the 
time of the early crude mills in the GO's designed for the manufacture 
of land plaster so highly valued by the farmers of that time, to the 
present mills equipped with modern machinery and to the present mines 
equipped in some cases with electrical appliances for convenient and 
rapid handling of the rock. 

There has been progress in the Michigan plaster industry though it 
has been slow, especially in the earlier mills. There are few places 
where so many experiments have been tried for improving the methods 
of manufacture of gypsum plasters, as have been performed in this State 
in the past years. Many of these early experiments proved to be failures, 
but out of the failures came suggestions which have proved valuable. 
From the records, Michigan seems to have been the first place where con- 
tinuous calciners were constructed, but these early attempts proved to be 

8 GYl'XUM. 

failures; and therefore it is difficult to convince a Michigan plaster man 
that such continuous kilns of the present time represent improvements. 
In Michigan the plaster calcining kettle was developed in its present 
form, though the first design came from New York. In this State we 
find further attempts to improve the plan of the kettle by adding more 
flues, 40 in one type, but the use of thpse kettles with numerous flues 
has been confined mainly to one plant. 

The manufacture of prepared sanded plasters is said to have started 
in Michigan, but other states now give a larger production. The largest 
gypsum quarry in the country is seen at Alabaster, Michigan, and there 
are few quarries that equal this one in facilities for work and in the 
purity of the rock. 

The first plaster combination in this country was formed in Michigan 
by the Michigan plaster men and was known as the Michigan and Ohio 
Plaster Association. The largest combination of plaster interests was 
started by Michigan plaster men and is known as the United States 
Gypsum Company. 

The invention of gypsum wall paint which made the finished wall a 
work of art, and which has attracted favorable attention in all parts of 
this country and abroad, was made by Mr. M. V. Church of Grand Rap- 
ids and named Alabastine. 

Michigan has been one of the pioneer states in the American gypsum in- 
dustry, and to-day it is one of the foremost states in a well developed 
gypsum industry. It is fitting then that a monograph on this subject 
describing not only the local deposits and local history, but also 
the industry as a whole in the United States and in the foreign coun- 
tries, should be issued by the State Survey of Michigan. 

§ 4. Rrief Summary of the Report. 

The distribution of gypsum throughout the world is described in the 
next chapter and the methods of manufacture in foreign countries are 
given in brief form, and a similar discussion of the distribution of 
gypsum in the United States is given, including the interesting secondary 
deposits of gypsum earth found in the southwest. A theory of origin 
is given. 

The third chapter gives a historical resume of the development of 
the gypsum industry in Michigan from the year 1827 to the present, and 
shows the gradual development of the industry through the experimental 
work of the pioneer plaster men of the State. 

In chapter four, the geology and topography of the Michigan Lower 
Carboniferous gypsum deposits are taken up in detail. The deposits cor- 
respond to the Osage (Augusta) of the Mississippi valley. This forma- 
tion outcrops around the border of the interior coal basin of Michigan, 
but it is covered over much of the area by the drift. The geology and 
topography of the drift are described in a pajier by Mr. Frank Leverett. 

Geological Survey of Michigan. 

Vol. IX Part II Plate II. 




Chapter five gives a brief account of the St. Ignace gypsum deposits on 
the Upper Peninsula, which are not of commercial importance at the 
present time. They differ from the other Michigan deposits in being of 
the uppermost Silurian or Salina age. 

Chapter six is devoted to the study of records of wells drilled in the 
State, which shows the distribution of the Michigan Group below the sur- 
face. In this chapter an attempt is made to estimate the quantity of 
available gypsum in Michigan, giving 138,000,000 tons, which at the pres- 
ent rate of production in the United States would supply the whole 
country for over 170 years. See Appendix A. 

A description of the Michigan mines and mills is given in the seventh 
chapter. There are seven mills now in operation, and two abandoned 
for the present, and one, the Powers mill, which was in operation when 
this report was first started, but was burned in the spring of 1903. 

In the Grand Kapids area the gypsum is found in two layers, an upper 
six foot ledge, and the lower twelve foot which is the one now worked 
at the quarries. The rock is mined in open quarry, in hillside slope 
entries, and by shafts. At Alabaster the gypsum ledge runs from 18 to 
22 feet in thickness. The Michigan mills are usually frame buildings, 
well constructed, and arranged so as to facilitate the rapid handling of 
the product, and they can produce a thousand tons of plaster a day if 
worked at their capacity. 

The process of manufacture is described in the eighth chapter, and is 
practically the same at all the mills. It consists of crushing the rock 
in jaw crushers, buhr stones, and emery mills, and calcining in 8 or 10 
foot vertical iron kettles. The products made are land plaster, dental 
plaster, plaster of Paris, retarded wall plaster, and Alabastine wall paint. 

This chapter includes a discussion of retarders, giving their composi- 
tion and effects on the plaster, which are not injurious when good re- 
tarders are used in small quantities. The set of plaster is shown to be 
due to the formation of a crystal network, and the different theories ad- 
vanced to explain the causes of the set of plaster are given. 

Chapter nine gives analyses of gypsum from the different parts of the 
United States and the world, and discusses especially the chemical com- 
position of Michigan gypsum which contains 94.7 to 98.3 per cent of lime 
sulphate plus water, or gypsum, leaving but a small per cent of im- 
purities. The analyses of finished plaster are also given showing the 
changes resulting from calcination. 

The tenth chapter deals with a rather new phase of gypsum examina- 
tion, and one often neglected in a discussion of gypsum, that of the phys- 
ical examination of gypsum plasters. The chapter devotes special atten- 
tion to the tensile, compression, and adhesion tests of the plasters. The 
work is based on a large series of tests extending over a period of two 


years, and should be of practical value to the gypsum companies of the 
State and of interest to all users of, and workers in, gypsum products. 

In the eleventh chapter the various theories of origin of gypsum are 
discussed and the conclusion reached that the Michigan gypsum is a de- 
posit through evaporation of an enclosed basin formed as a gulf in the 
old Osage sea and finally cut off from that gulf. The conditions then 
present are regarded as analogous to the present Caspian Sea. 

The twelfth chapter treats of gypsum as a fertilizer and should be of 
interest to the farmers of the State, as it includes a summary of experi- 
ences and theories collected from various sources over the world. This 
is a much disputed subject and the conclusions reached are rather against 
the value of gypsum as a fertilizer under ordinary circumstances. 

In chapter thirteen the uses of calcined and uncalcined gypsum are 
enumerated and described. The variety of uses of gypsum is somewhat 
a matter of surprise to persons who have an acquaintance with but a 
few of them. 

Appendix A consists of a series of tables of statistics of gypsum pro- 
duction in the world and in the United States. It is seen from these 
tables that Michigan has produced since the beginning of the industry 
2,587,656 tons of gypsum with a value of $9,528,805, one-half of this 
amount was used as land plaster and one-half was calcined. The greatest 
production was in 1902 when 240,227 tons were mined of which 69 per 
cent was calcined. Michigan has held for some years first rank among 
the states of Ihe Union in the production of gypsum. 

Appendix B gives references including a bibliography of all the works 
so far found by the writer which treat in any way of gypsum. Most of 
these works were consulted in the preparation of this volume. 



§ 1. England. 

The principal deposits of gypsum of commercial importance in Eng- 
land 1 are near Fauld in Staffordshire, Chellaston in Derbyshire. King- 
stone-on-Soar: and Newark in Nottinghamshire, Carlisle in Cumberland, 
Kirkby Thore in Westmoreland, and Netherfield in Sussex. In addition 
gypsum is found near Watchet in Somersetshire, near Penarth in South 
Wales, at Swanage, near Alston in Cumberland, at Shotover Hill in Ox- 
fordshire, and in Cheshire. 

The rock occurs in nodules and in lenticular and irregular masses up 
to fifteen feet in thickness, but as a rule not in regular beds of large 
extent. In age the principal deposits of British gypsum occur in Keuper 
marls (Trias), but in Cumberland and Westmoreland the mineral occurs 
at a lower horizon in the Red Beds (Permian). The Sussex gypsum is 
found in Purbeck strata (Jurassic). 

The gypsum in the Purbeck strata in Sussex was discovered in making 
the Sub-Wealden boring which was commenced in 1872. The gypsum in 
the Triassic formations has been worked for many generations. 

The purest British gypsum is a snow white granular or crystalline 
rock. It is usually colored by oxide of iron producing brown irregular 
veins and markings. Some of the gypsum occurs in nodules of pink 
color. The origin of the gypsum in England is generally ascribed to 
precipitation from inland bodies of salt water. 


The purest crystalline gypsum known as alabaster is largely worked 
in England as an ornamental stone, especially for interior ecclesiastical 
work, and for inlaid panels in halls and on staircases. It is ground to 
flour and calcined into plaster of Paris, and then is used for ceilings, 
walls, mouldings, and is a principal constituent in many patent plasters 
and artificial marbles. It is used to a limited extent in paper and glass 
manufacture, and also in the preparation of certain pigments and phar- 
maceutical products. The largest gypsum mine in England was the 

'The writer is Indebted to Prof. John W. Judd and Mr. Budler of London for most of the inform- 
ation concerning the gypsum of England. 


Chellaston plaster mine in Derbyshire, but in 1890 the production ceased. 
The largest plaster mill in England is the Vale of Belvoir and Newark- 
on-Trent Plaster Company mill at Newark-on-Trent. 
The amount of gypsum quarried in 1900 in England was as follows: 

Tons. Value. 

Cumberland 41,794 £8,359 

Derby 10,289 4,630 

Nottingham 77,492 32,208 

Stafford 47,736 15,700 

Somerset 5,110 1,265 

Sussex 17,768 5,730 

Westmoreland 7,849 1,750 

Total 208,038 £69,642 

§ 2. Australia. 1 

Gypsum occurs in layers in the Rolling Downs formation (Lower 
Cretaceous) in Western Queensland in conjunction with conglomerates, 
sandstones, shales, and gypseous marls. As a rule these beds are thin 
and the gypsum is generally massive in structure and is milky white in 
color. It is found sometimes crystallized as selenite. 

Gypsum also occurs in the Desert Sandstone formation (Upper Cre- 
taceous) where it occurs as layers in sandstone and generally with fibrous 
structure. It is often observed in close proximity to the opal deposits 
of this formation. Gypsum has been found in small quantities in a 
few other localities in Queensland. 

§ 3. India. 8 

In India, gypsum of economic importance is of rare occurrence. A 
small supply comes from southern India. In several of the outside 
regions it occurs in inexhaustible quantity but often difficult to reach, 
so that most of the gypsum used is imported. 

Madras: Trichinopoli District. — According to Mr. H. Blauford 3 this 
mineral is abundant in many parts of the Cretaceous rocks of this dis- 
trict. It is generally somewhat impure, occurring in concretionary 
masses and plates. It would answer when made into plaster of Paris 
for taking moulds, but not for casts where whiteness is required. It 
seldom occurs in sufficient quantity to be worth collecting, though plates 
of pure selenite are obtainable. It is most abundant in the Utatur beds, 
especially in the belemnite clays to the east of Utatur, and in the unfos- 
siliferous clay to the northeast of Maravuttur. 

Chingleput District. — In the clayey estuarine beds to the north of 
Madras, 4 concretionary masses of gypsum and crystals of selenite occur, 

•The information in this section was obtained through Wm. H. Rands, Government Gologist for 

'The following is Mr Ball's account of the deposits of India furnished to the writer by Dr. J. Le 
Griesbach, Director of the Geological Survey of India. 

« Memoirs Geol. Survey of India, Vol. IV, p. 214. 

* Vol. X. p. 132. 


but not in any abundance. According to Mr. Foote, supplies for making 
plaster of Paris for use in the Schools of Art at Madras have, however, 
been obtained from this source. 

Nellore District. — In the eastern coastal districts of which Nellore is 
one. crystals of greater purity than those found near Madras are said to 
occur. It is considered by Mr. Foote 1 that they might be collected in the 
neighborhood of the canal and forwarded to Madras, where the con- 
sumption is increasing. 

Bombay District. — Gypsum in the form of selenite is found in small 
quantities in the marine deposits about Bombay and in Kattywar, and 
it is stated to occur in parts of the Deccan in connection with deposits 
of salt. But the principal sources of gypsum in this Presidency were 
situated in Cutch and Sind. 

Cutch. — The following is Mr. Wayne's 2 account of the distribution of 
gypsum in Cutch: Large quantities occur in shales belonging to the 
Jurassic, Sub-Nummulitic and Tertiary groups; the most highly gypsif- 
erous being those of the Sub-Nummulitic band. The mineral is generally 
translucent; and clean blocks, several inches in diameter, may be found 
weathered out on the surface of the ground. 

Although much of it might l)e obtained without any great trouble, it 
does not appear to be utilized except to a slight extent by goldsmiths, 
who are said to use it in a powdered state for polishing their wares. 

Sind. — Several writers on the geology of Sind allude to the occurrence 
of gypsum. According to Mr. W. T. Blanford 3 it is found in some abund- 
ance near the top of the Gaj beds of the Kirthar range; the beds of it 
are not unfrequently three or four feet thick. Two such beds of different 
degrees of purity are exposed in the section of the banks of the Gaj river, 
and similar beds occur not infrequently further in the north. 

Dr. Buist 4 has called attention to the fact that in Sind the art of mak- 
ing plaster of Paris was known to the natives, and that it was employed 
in casting lattices and open work screens for the top of doors, etc., where 
a free circulation of air was desirable; the dryness of the climate in Sind 
protects it from injury on exposure. 

Baluchistan. — It is probable that in the continuation of the Sind beds 
northwards into Baluchistan similar beds of gypsum will be found to 
exist. That it actually does exist is known, but details are not yet 

Afghanistan. — Near Kandahar gypsum is obtained from lenticular 
masses and veins in the Gaj formation and in the post-Pliocene gravels. 
Capt. Hutton states that 'the plaster is largely used in the buildings of 
that section. It was first discovered in the time of Ahmed Shah, who 

'Memoirs Geol. Survey of India. Vol. XVI. p 104. 

> " " Vol. IX. p. 90 

* " ' " Vol XVII. p 195. 

*Trans. Bomb. Geol. Soc'y. (1852). Vol. X. p. 229. 

14 0PY8UM. 

considered it so valuable that he caused public prayers and thanksgivings 
to be offered up, and celebrated the event with feasting and the distribu- 
tion of charity. 

Punjab. — Gypsum is found in Kalabagh and in the Khasor range, but 
it is not at the present time utilized. Both here and also at Mari and 
Sardi, quartz prisms with pyramidal terminations are found in great 
abundance in the gypsum and they go by the name of Mari diamonds. 

Kohat District. — In this district gypsum is very abundant. It might 
be obtained by open quarrying in any quantity, but it is not worked. 
The crops, especially the wheat, which are raised on the soil resting 
on the gypsum at Spina are said to be finer than those in any other part 
of the country. 

Salt Range. — In those portions of these districts which include the 
salt range, gypsum occurs in enormous quantities associated with the 
salt marls of the Silurian or the Pre-Silurian age. Some of the most 
compact varieties near Sardi are manufactured into plates and small 
ornamental articles. 

Spiti. — Very considerable deposits of gypsum are found in the Spiti 
valley. The origin is traced to the ordinary chemical reaction between 
iron pyrites and carbonate of lime. 

'North-West Provinces. — In this district, gypsum in lumps and veins 
is found in the rocks of Tertiary age and older rocks. In origin, this 
gypsum is secondary and it is used to some extent for interior decora- 

In the Kamaun and Garhwal districts gypsum is found in considerable 
amount and is used for plaster in a number of places. 

§ 4. Tasmania. 1 

Gypsum does not occur in Tasmania in deposits of economic impor- 
tance. It occurs in lumps and veins in Tertiary clays near Launceston, 
also in benches in serpentine rock associated with talc at Trial Harbor. 
It also occurs in Permo-Carboniferous limestone, but none of these oc- 
currences are of any economic importance. 

§ 5. Canada. 1 

In the Salina formation of the Upper Silurian in Canada occur exten- 
sive beds of gypsum, which are not continuous for long distances, but 
appear as detached dome like masses sometimes one-fourth of a mile 
long. The gypsum is interstratified with dolomite, and is often separated 
by beds of it. The workable beds are seen on the Grand River twelve or 
fourteen miles above its mouth and are traced to the town of Paris. 

'Note furnished the writer by W H. Twelvetrees, Government Geologist at Launceston. 
SQeology of Canada, 1863, pp. 847, 762. 

Minerals of Nova Scotia. Gilpin, 1901, pp. 56-57. 

The Mineral Wealth of Canada. Wilmott, 1897, pp. 105-111. 


On the left bank of the river near the town of Cayuga is a large deposit 
of gypsum covering about 60 acres. 

Gypsum is also found in this same area near York, in Indiana, and Mt. 
Healy, where the ledge is three and one-half feet thick. The gypsum at 
York is seven feet thick but separated into several layers, the thickest 
of which is two feet. The gypsum is traced from here two miles to 
Seneca and it is found twenty miles north near Brantford. 

Near Paris there are two beds of gypsum nine feet in all. The gypsum 
formation outcrop extends from the Niagara river to the Saugeen on 
Lake Huron, a distance of 150 miles, but most of the mines are within 
a distance of 35 miles on the Grand river expending from Cayuga to Paris. 

Large deposits of gypsum are found on the Magdalen Islands in strata 
of Carboniferous age and are shipped into Canada. 

In Nova Scotia the gypsum beds vary from a few inches to a hundred 
feet in thickness and are found in the Lower Carboniferous formation, 
possibly nearly equivalent to the Lower Grand Rapids or Michigan series 
of Michigan. The chief localities where the mineral is worked are, 
Windsor, Cheverie, Maitland, Walton. Hantsport. Wallace, Mabou, Anti- 
gonish, Lennox, St. Ann's, and Big Harbor. Gypsum is shipped in the 
crude state to the United States mainly from the Windsor district and 
some from Cape Breton. 

Gypsum is found in large amount in New Brunswick. It is quarried 
at the Albert mines, where the rock is 00 feet thick, and it is calcined at 
the large works at Hillsborough. 

Gypsum occurs in northern Manitoba in two beds, 22 and 10 feet thick, 
and northwest along the Mackenzie river; also, in the Salmon river, in 
British Columbia. 

In 1002 the Canadian production of gypsum was 332,045 tons. 

§ 6. Cyprus. 1 

Gypsum deposits are found in many parts of the Island of Cyprus, 
but the deposits worked are near Larnaca on the east and Limasol on 
the west coasts. The stone at Larnaca is said to be the best, and there 
are large deposits at both places. The stone appears on the surface for 
miles around these two places, and it is quarried by the natives and 
hauled in carts to the factories. There are two factories at Limasol 
which have been in operation for the past five years, and one factory at 
Larnaca erected about fifteen years ago. These mills cannot supply the 
demand for the plaster. About 200 tons are sent annually to Turkey and 
7.000 tons to Egypt. 

The plaster kilns are built of fire-proof stone in the form of a small 
room eight or ten feet square, with arches made of the stone two or three 
feet high, and on these arches the gypsum blocks are placed and a fire of 

•Information furnished by Dr. W. M. Moore of Larnaca, Cyprus. 


brush wood is built under the arches. After burning Ihe stone is crushed 
in mills which have been brought from England and France and operated 
by steam power. 

The plaster is of three grades according to the fineness of the grind- 
ing. The color of the plaster is gray and not white. It is used for 
plaster of Paris and for building purposes. 

§ 7. France. 1 

The French gypsum in the neighborhood of Paris has given the name 
to the calcined product the world over, so that at the present time plaster 
of Paris is a world product as well as a French one. As the Paris region 
i is apparently the home of this industry, it may l>e of especial interest 

to examine the geology and the methods of working of the gypsuni de- 
posits of that region. 

The gypsum quarries are located at Mont-martre, Pantin, Belleville, 
Sannois, and Enghien, in the Tertiary deposits of the Paris basin made 
famous by the paleontological studies of Cuvier. 
t The varieties of this gypsum are designated as, 

le gyp8e filamenteux confusedly crystalline. 

i le gypae feuillet6 selenite. 

; le faux alabfttre alabastrite. 

' le sulfate de chaux calearifere ordinary gypsum. 

' There .are three main strata of gypsuni in the Paris basin. The lowest 

j is composed of beds of gypsum with a large proportion of selenite, in this 

I mass there are five beds with a total thickness of seven feet seven inches. 

j This stratum is seldom worked because it makes a poorer quality of 

i plaster and is difficult to mine. 

' The second and third strata are separated by beds of marl and are 

about five feet in thickness, but vary in different parts of the basin. At 

Mont-martre the second stratum is 33 feet and has eight workable beds. 

One of these beds at Belleville called the "big vein'' fie gros banc) is 

often used for artistic plasters. 
j The thickness of the gypsum series at Mont-martre is 1G0 feet, and at 

I Sannois it is nearly 180 feet, at Enghien it is about 100 feet. A section 

' near Paris shows the following order of rock strata : 2 

I 8. First layer of gypsum or principal mass of gypsuni. 

' 7. Marl. 

! 6. Marl with kidneys of gypsuni. 

5. Second layer of gypsum with marl (containing shells of Cerithus). 
; 4. Yellow marl (with shells of Lucina inornata). 

3. Third layer of gypsum. 
] 2. Marl (with fossils of Pholadomy a htilcnxix). 

! 1. Fourth mass of gypsum. 

•For sources of this information see under France in Bibliographic list. 
i ?Lapparent, Geologic, p. 1163. 







The first layer of gypsum is the most constant, most extensive, and 
usually the thickest (reaches 65 feet at Mont-martre) in the Paris area. 
It marks the horizon of mammalian fossils described by Cuvier and it is 
characterized by a prismatic parting which, has given the name of the 
tall pillars (hauts piliers). 

The Paris gypsum is remarkable for its high percentage of lime car- 
bonate amounting to 10 and 12 per cent. Many have ascribed the high 
quality of French plaster to the presence of this material, and it has 
given support to a theory of peculiar origin of the gypsum, namely, that 
the gypsum is due "purely to a fresh water deposit produced by a river 
whose waters are highly charged with lime sulphate, somewhat like the 
La Frume Salso in Sicily described by Lyell" (Burnell). According to 
Lapparent, the origin is lacustrine and the gypsum was formed in la- 
goons or sheets of water near the shore of the ocean, and represents a 
direct precipitation of gypsum and not a transformation of any beds of 

The gypsum is quarried in open cuts, by shafts, and by driving gal- 
leries into the hillside. The last is the most common method and is fol- 
lowed at the Mont-martre, Triel and Belleville quarries. 

Method of Calcining Gypsum in France. 

There is a marked contrast in the methods of burning gypsum in 
France and in the United States. Most of the American rock is calcined 
in kettles by direct heat, and even where rotary cylindrical kilns are 
used, the heat is direct. The French plaster manufacturers have in- 
vented a variety of kilns and methods which are held in high favor by 
the companies using them. 

One of the common types of kilns is described as a much simpler ar- 
rangement than the American kettle and would seem to represent a more 
crude method. A series of arches (see Figure 5 a ) are constructed out of 
gypsum blocks and supported on piers of the same material. These 
arches are about one foot eight inches wide and two feet four inches high. 
On these are placed large blocks of gypsum then smaller and smaller 
blocks, until the kiln is filled to a height of about 13 feet. The whole 
kiln is covered by a shed roof, and spaces are left between the blocks to 
give a draft. The arches are filled with wood and a hot fire maintained 
until the lower blocks begin to glow red hot, which requires about 10 
hours, then a slow fire is kept for 10 to 12 hours. The lower rock over 
the arches is overburned and the upper rock is underburned, but a mix- 
ture of the whole gives a fairly uniform plaster. Such a kiln holds 70 
to 75 tons of rock and the plaster is removed in from two to three days, 
and requires 1,200 fagots of wood which formerly cost twelve to fifteen 
cents per hundred. These fagots now cost 40 cents a hundred, and many 
kilns now use part coal in the form of briquettes. 


In the province of Sa6ne and Loire, coal is used for calcining and it 
requires about 1,120 kilogrammes of coal to calcine 25,000 kilogrammes 
of plaster. In the manufacture of land plaster the gypsum is often 
burned in lime kilns to render the rock friable and easily broken. 

Improved Types of Kilns in France. 

The kiln described above is said to be used more commonly than any 
other, but a number of plaster works are now using improved kilns 
where the heat is usually indirect. The Brisson kiln used at Pantin is 
analogous to a gas furnace in construction. It has eight retorts, each 
holding two hectoliters of gypsum, heated by a single fire, attended by a 
single workman, and yielding a very white plaster. The plaster made in 
the rough kilns described above is usually gray in color, and it was form- 
erly considered by plasterers in France that gray plasters were always 
superior in quality to white, so for a Jong time any process making a 
white plaster was looked upon with suspicion. 

Kiln of Ramdohr. 

In the continuous kiln of Ramdohr, there are a series of retorts placed 
in vertical rows opening above. These retorts are oval in section and 
made of separate pieces united with cement collars. The retort is heated 
by direct fire in the upper two-thirds of its length, and the lower third 
measuring one metre serves to partially cool the plaster. The removal 
of the finished plaster is effected by the aid of three conical valves below 
moved by a crank and pinion. One man can handle a battery of seven 
to nine retorts. Each retort calcines in twenty-four hours six charges 
of six hectoliters, or 36 hectoliters, and consumes 600 kilogrammes of 
lignite or 200 kilogrammes of coal. (One hectolitre — 150 kilogrammes, 
or 330 pounds.) 

Continuous Gypsum Kiln of Hanctin . 

This method differs from all those so far described in that the gypsum 
is pulverized before the calcining. The furnace is composed of a tubular 
bundle lightly inclined, all bound together and moved by a shaft with 
a moderate rotation. The flame circles around these tubes and the gyp- 
sum in descending slowly comes under the influence of the heat. The 
powdered gypsum is thrown into a hopper over each tube. By regulating 
the length of the tubes, and the inclination, a uniform calcination is 
said to be secured. In some of the Paris plants the heat for calcination 
of the gypsum is secured by forming gas in a generator and conducting 
this to the center of the gypsum furnace. 

Calcining Plaster by Vapor of Superheated Water. 

In this system of Violette, there is a generator or heater for water 
vapor connected with a serpentine metal coil. The gypsum rock is 



placed in a double receptacle in a wall of masonry. It is oval in form 
with two openings opposite each other which can be hermetically sealed 
and which serve to charge and discharge the plaster. A thermometer 
is used to determine the temperature of the entering vapor. 

The vapor formed in the generator circulates in the serpentine coil and 
heated to the proper temperature enters the tirst receptacle, reaching 
all parts of the rock and calcines it gradually and equally. The vapor 
then passes into the second receptacle and acts upon the rock, and then 
escapes into the air carrying all the moisture of the gypsum, on account 
of the high temperature of the vapor. The process depends upon the 
principle that superheated water will absorb water. 

M. Tested Beauregard has modified this system and injects upon a hot 
surface in a specially constructed kettle, a thread of water which is 


Fig. 5. Gypsum kiln: (a) common type. 

(b) Dumesoll kiln, used in France. 

changed to vapor. This vapor is then heated in a powerful heating 
retort to as elevated a temperature as required for calcination, which 
is regulated in a constant manner. These methods have certain theoreti- 
cal advantages and certain practical difficulties. The apparatus used 
is simple in construction and small volumes of water are used. The 
quality and beauty of the finished product are of the best. On the other 
hand it is difficult to keep the temperature at 200° C, as usually re- 
quired and there is a tendency of the vapor to drop in temperature and 
to condense in the midst of the material to be dried. 

Dumesnil Kiln. 

Another variety of kiln held in high favor in. France is the Dumesnil 
kiln shown in Figure 5 D This has a central fire pit (G) with a fire 
chamber (B) above, which is connected with radiating flues (EE) con- 


structed of the larger fragments of the gypsum rock. Above these flues 
the stone is arranged in layers containing smaller and still smaller 
fragments toward the top. In the arch (L) forming the top of the kiln 
are flues (AAN) controlled by dampers. The gypsum is charged through 
the opening at C and removed through a door at the side. Coal is used 
as fuel and is added at H. The ash pit is located at I. The kiln is 20 
feet in diameter and 13 feet in height to the top of the arch. It will 
hold (35 cubic metres) 1,200 cubic feet and it is burned in twelve hours 
with a fire of fagots and a little less with coal. The method is said to 
be economical, and the plaster is uniform in quality. 

§ 8. Germany. 

Hartz Mountains District. 1 

In the southern part of the Hartz, gypsum is found near the top of 
the Zechstein formation (Permian) from Osterode, Sterna, and Sachsa 
on the west to Mohrungen and Obersdorf near Sangerhausen on the 
east, a distance of six miles. In places it forms mountains as Katzen- 
stein near Ostrode, Kohnstein at Ilfeld. 

The rock is almost compact, white in color, or in places colored slightly 
gray through the presence of bituminous matter. It has been formed 
through anhydrite altered by inflowing water. 

The gypsum industry centers at Ellrich, Walkenried, and Osterode, 
also in Tettenborn, Niedersachsweisen. At Sangerhausen, some 16,500 
double wagon loads of gypsum are worked annually. In Thuringia near 
the Hartz, gypsum layers in the Bunter sandstein of the Trias are worked 
at Frankenhausen ; and in the Keuper of the Trias at Walschleben, 
Elsleben, and Gispeileben north of Erfurt. 

Mode of Calcining. 

The gypsum is ground on mill stones, each a set of three of 600 mm. 
(23.4 inches) diameter. The middle stone revolves w r hile the other two 
remain stationary. It takes from five to six H. P. and grinds about 1,200 
kilogrammes (2,640 pounds) per day. The plaster is calcined in iron 
kettles set in masonry and the material is kept in motion by revolving 
stirrers. (See Figure 0.) At Osterode one mill uses a round iron vessel 
as a muffle kiln for burning the plaster. 

In Ellrich and Walkenried some double shaft ovens four metres (13 
feet) high and one and one-half metres (nearly 5 feet) in diameter are 
used. The fuel and gypsum are placed in these shafts in alternate layers 
and covered with a shed roof. As soon as the plaster is completely cal- 
cined it is drawn out below and more material added to the top. 

For 100 years the Hartz gypsum plasters have been used in cellar walls, 

•Die Gypsindustrle Im Han, M. Gary, Thonindustrle, 1899, Vol XXI [I. pp 1079-108* 



gates, etc., the plaster mixed with small river pebbles, and some of these 
arches with ten metres (32 feet) span are still solid. 

Other German Localities. 

Gypsum is found near Frienwalde and Muskau, at Sperenberg, Lune- 
berg, Seegeberg in Holstein, Rudersdorf near Berlin, in Lowenberg in 
Silesia, and in the northern border of the Thuringian forest as at Rhein- 

In some of the primitive mills the rock is broken in stamp mills. The 
stamps are made of maple or oak with an iron shoe at the bottom giving 
a length of 2.825 metres (9.1 feet). These fall in a trough of wood with 

PiK 6. German plaster kiln. 

an iron grate bottom. It is ground finer in a roller machine in which 
heavy rollers move over a pan somewhat like an American dry-pan brick 
machine. These rolls make 50 revolutions per minute and are 314 mm. 
(1.25 feet) in diameter and 200 mm. (10 inches) in breadth. In some 
mills a jaw crusher is used not very unlike the type used in the Michigan 
mills, and the fine grinding is then accomplished by means of mill stones. 
These are about 40 inches in diameter and make 120 to 130 revolutions 
per minute. They require four IF. P. for grinding plaster and five or six 
H. P. for the unburned gypsum. 

Gypsum 1 is found in the Triassic formations of the district of Treves 
in the upper valley of the Moselle near the province of Luxemburg. In 
this region gypsum is found in the Muschelkalk rocks (Trias) near the 

'From information kindly furnished by Dr. O. Follman, Cobientz. 


villages of Igel. AYasserbillig, Oberbillig, and Temmels, and the stratum 
is nine metres (20 feet) thick. 

At Welschbillig the gypsum near Oik is six metres thick and in the 
same formation of the Musch^lkalk are the gypsum layers of Wallendorf 
in the eastern part of Prussia, 15 metres (about 49 feet) thick. In 
Westphalia at the Godensdorf the gypsum is four or five metres thick, 
and at Minden it is three metres (9.7 feet), all of these being in the 
Muschelkalk. In a number of places gypsum is found in thin seams and 
layers in the Bunter sandstein of the Triassic formation. 

A most excellent account of the process of the manufacture and uses 
of the gypsum in Germany has recently appeared, and it was written 
by Prof. Wilder of Iowa in Volume XII of the Iowa Geological reports. 
Mr. Wilder personally visited the mines and mills. According to this 
writer the German gypsum industry centers especially in the Hartz 
mountains near the village of Ellrich, in Thuringia near Possench and 
Krolpa, and at various towns on the Rhine near the mouth of the Neckar. 
The three varieties of calcined plaster sold in Germany are: ik stuck" 
gypsum used in plastering walls and for building-blocks or boards and 
for ornaments and imitation marble; u estrich ,% gypsum burned at a 
temperature of 500° C. and used for making a very hard plaster used 
especially for floors; "porcelain" gypsum used for porcelain ware moulds. 

§ 9. Switzerland. 1 

The gypsum of Switzerland is mainly in the Triassic formations. It 
is found in abundance in the Trias of the Jura and of the Rhine border, 
also in the Alps. Small deposits occur in the Purbeck (Upper Jura) 
of the Jura mountain region, and veins of fibrous gypsum are found in 
the Lower Miocene. 

The gypsum varies in thickness in different localities and it is usually 
white or gray in color. It represents a deposition from concentrated 
sea water. The chief localities for these gypsum deposits are in the 
anticlinal valleys of the Bernese and Argovian Jura, Villeune parish of 
Ollon, in Bex, in the Valois, Cherret, and several other places. There 
are extensive plaster quarries near Pouterliers. 

§ 10. Sweden. 

According to Dr. Henrik Sautesson, gypsum occurs in Sweden in very 
small quantity in a few places, but it is of no economic importance. The 
plaster and gypsum used in that country are imported. 

§ 11. Italy. 

It has been difficult to collect information concerning the gypsum 
deposits of Italy. Alabaster is worked at a number of places, the purest 
is that of the Val di Marmolago near Castellina, 35 miles from Leghorn, 

1 1nformation furnished by Prof. E. Chuard of Lausanne. 


and it is very popular for the manufacture of ornaments. A white wax 
like variety comes from Volterra and a granitic variety comes from 


§ 12. General Remarks. 

Gypsum deposits are found in most of the states and territories of this 
country (see map, PI. XIII), and are worked in many of them. The in- 
dustry is small even in some of these areas where the supply is almost un- 
limited. Sparsely settled districts have small demand for gypsum prod- 
ucts, and a number of the largest deposits are located at a distance from 
the railroads. 

The industry is well established in a number of states and it is being 

started in others. A brief review of some of these districts will now 

, be given. It was hoped that this review would be more nearly complete, 

but many of the companies refused to give any information about their 

work or the deposits. 

§ 13. New York. 

The facts given for New York state are taken mainly from the reports 
of the State Museum especially by Merrill, Clarke, and Parsons. The 
gypsum deposits of the state occur in the Salina or higher formations 
of the Upper Silurian period and occur in regular beds which show that 
the gypsum was originally deposited from water. Mr. Clarke states in 
his report that no evidence of gypsum is found east of Madison county, 
and that toward this eastern limit the gypsum is of a darker and more 
earthy type, probably due to the presence of carbonaceous matter. The 
dark variety lies nearer the surface, while the whiter gypsum at the west 
is generally heavily eapj>ed with rock and has less thickness than the 


The quarries at Fayetteville are located about two miles southwest of 
the village and there are five companies engaged in the work. The 
Severance quarry has been worked for over GO years, and it shows the 
greatest thickness found in the state, GO feet, and consists of 8 layers 
18 inches to 30 feet thick, and the gypsum is overlain by shaley rock. 
The amount of lime sulphate is greatest in its crystalline layers and 
least in the brown layers. It runs from 80 to 00 per cent of lime sulphate. 

The rock is mined by stripping off the surface shaley layers. Three 
beds are distinguished in this quarry of which the upper is 30 feet thick 
and lighter in color. The product is sold to local mills and hauled one 
and one-half miles to the Erie canal where it is shipped to outside 
points. The quarry covers three acres and it is estimated to cost twenty- 
five to thirty cents a ton for mining. The average output is 5,000 tons 
a vear. 


Adjoining the Severance quarry are the quarries of the National Wall 
Plaster Company, where the gypsum is present with the same character 
as at the other quarry. The area is about five acres and the mill of 
this company uses the Cummer process of rotary calciners described 
under the chapter on technology. 

East of these quarries there is a fifteen acre tract of gypsum owned by 
the Adamant Wall Plaster Company. This tract was abandoned for a 
number of years. Smaller quarries are found in the same section. 

Cayuga Plaster Compatiy. 

The largest quarries in the state belong to the Cayuga Plaster Co., of 
Union Springs, four miles west of Cayuga. The original gypsum area 
was about one mile square on the east shore of Cayuga lake and was 
opened in 1828. The output is about 10.000 tons of plaster and 5,000 
tons of rock gypsum annually. 

The gypsum is covered w r ith earth and underlain by limestone. The 
color of the rock is gray with plates of selenite more or less intermingled. 
The rock has a maximum thickness of 40 feet with an average of 8 feet 
of top rock and 8 feet of bottom rock. The gypsum runs about 80.8 per 
cent lime sulphate. The other quarries in this section are small and have 
been worked from time to time. 

Wheatland Land Plaster Company. 

The Wheatland quarry is located about three and one-half miles from 
Caledonia, and the gypsum occurs in three layers, the middle one being 
the best. The deposit is six feet thick and is worked through a tunnel. 
The rock is used at the mill near at hand, with a capacity of 40 tons 
a day. A' mile east at Garbuttsville is the mine and the mill of the 
Lycoming Calcining Company. The rock at this mine is worked through 
a tunnel 200 feet long and the mill has a capacity of 00 tons in ten 

Oakfield Gypsum Deposits. 

At Oakfield in Genessee county, there are three companies working the 
gypsum deposits. The United States Gypsum Co. has the largest mill 
and operates two mines about 40 feet deep, reaching the gypsum rock 
which is four feet thick. They ship annually 15,000 tons of rock to the 
Pittsburg plate glass factories and calcine about 10,000 tons. The gyp- 
sum at these mines is of high degree of purity and snow white. Eighty 
feet below the first bed of gypsum is a second, ten feet thick, not worked. 
The other companies have five mines, and all use the kettle process of 

The farthest west gypsum worked in New York state is in these 
Oakfield mines. Drilling, however, shows that under Buffalo at a depth 



Dtviiiofi Lin*t of Strata 

Proiwbk £itt*nt of Work 
tbka B*di of Gytttufn 

Outcopt ol SiemiA 


Outcropf oT Lima*l«n* ot 
— Michigan «y»ji« 



of 50 feet there is a deposit of over 25 feet of white gypsum. Attempts 
were made a number of years ago by the Buffalo Cement Co. to mine 
this layer by sinking a shaft, but the inflow of water stopped the work 
and it was abandoned. 

Twelve companies are engaged in working the gypsum quarries in 
New York state. 

§ 14. Ohio. 

The Ohio gypsum area was visited by the writer in the summer of 
1902 and the following notes obtained which were supplemented by 
reference to the reports of the Ohio Survey. Gypsum is quarried in this 
state at the single locality near Gypsum station, Ottawa county in the 
northern part of the state, ten miles west of Sandusky. 

The Fletcher mill is equipped with two ten foot kettles and the rock 
from the quarry is dried in a rotary drier with a daily capacity of 110 
tons requiring one-half ton of coke a day. The mill is connected with the 
mine by an incline track. The gypsum was formerly mined by stripping, 
but now it is mined through a double entry mine which runs info the hill 
about 400 feet. A section of the mine shows 16 feet of clay then three feet 
of shale above the gypsum which runs from five to seven feet thick and 
rests on four feet of limestone, below which is another stratum of 
gypsum four feet thick not worked in the mine. The mill was built in 
1898 and is now owned by the United States Gypsum Co.. and has a 
daily capacity of 100 tons. A new company has constructed a shaft 
one-fourth of a mile east of this quarry and expect to build a mill this 

The oldest mill in this state is a couple of miles west of the Fletcher 
mill and was first built in 1872 by Marsh & Co. though this company 
was organized in 1846 when they built a mill at Sandusky which was 
supplied with rock from this locality near Gypsum. In 1885 the plant 
was doubled in capacity and again doubled in 1890 and now has a daily 
capacity of 200 tons. 

The Marsh quarry was worked for many years in open pit by stripping 
off the cover, but since 1890 they have secured the gypsum through a 
tunnel into the hill. They have now constructed a shaft on a new 
tract to the west of the mill, 46 feet deep, and the stone is hauled from 
this mine to the mill on an overhead track. The mines are to be worked 
with electric drills and the rock brought to the surface by an electric 

The gypsum is covered with 24 feet of soil and shale which rests on a 
three foot gypsum ledge separated from the eight foot vein by one foot 
of blue limestone. The floor of the quarry is a calcareous shale one foot 
thick resting on a layer of impure gypsum for or five feet thick. The 
rock from the quarry is dried in a rotary drier 33 feet long and 6 feet in 


diameter aud is crushed in a large Champion crusher. There are four 
eight-foot Butterworth and Lowe calcining kettles. The fine grinding 
is accomplished by six ordinary buhr mills and the rock flour is reground 
for certain purposes in a twenty-four inch emery mill. The rock is 
stored in long sheds with a capacity of 12,000 tons. The rock is white in 
color and over 90 per cent pure. 

The geological age of the deposits is Upper Silurian, Salina, or 
Lower Helderberg of Orton, a formation with maximum thickness of 700 
feet. The gypsum occurs through it at various places, and the mineral is 
found in most of the deep wells drilled in northern and central Ohio. 
The gypsum beds, according to Orton, are not even and horizontal, but 
are found in waves and rolls, whose summits rise five to eight feet above 
the general level. The main plaster beds are about twelve feet thick and 
would yield about 50,000 tons to the acre. 

Xo fossils are found in the formation, and Orton regards the origin 
of the gypsum as due to a deposit from a shallow, land locked and 
contracting sea during this period. The shallowness of this sea is shown 
by the sun cracks and wave marks that are well shown in these rocks. 
The annual production of gypsum in Ohio is over 51,000 tons. 

§ 15. Pennsylvania. 1 

Tn Pennsylvania gypsum occurs in the Lower Helderberg in the seams 
intermingled with mud veins and the whole series lies just below a drab 
impure limestone. The origin has been regarded as due to an alteration 
of the limestone to gypsum through the agency of sulphur spring water, 
but it occurs at the same point in the geologic column as that of Ohio. 
The deposits are not of economic importance. 

§ 10. Virginia. 2 

The important gypsum deposits in Virginia are found in the south- 
western part of the state in the valley of the North Fork of the Holston 
river in Smyth and Washington counties. The deposits have probably 
been formed through the evaporation of an enclosed sea basin and they 
are of Lower Carboniferous age. The rocks are faulted, and the gypsum 
deposits are found north of the main fault known as the Saltville fault. 

The gypsum deposits in Holston Valley area commence three miles 
west of Chatham mil where about 300 tons a year are quarried. At 
Saltville there are several quarries where the gypsum is ground for land 
plaster or shipped to Glade Springs where it was used in the manufacture 
of Keene's cement until 1902. 

The largest mines are located southeast of Saltville at Plasterco and 

•Geol. Survey of Penn., Summary Final report, Vol. II. pp. 913-915. 

•Eckel. Salt and Gypsum Deposits of Southwestern Virginia, U. S. Oeol. Survey. Bull. 213, pp. 408- 
461 : 1903. Stevenson, The Salt and Qypsum Deposits of the Holston Valley, Virginia, Proc. Araer 
Philos. Soc. Vol. XXII, pp. 164-161 : 1884. 

Boyd. Resources of Southwest Virginia, pp. 104-108: 1881. 


belong to the Buena Vista Plaster Co. The gypsum stratum is 30 feet 
thick and dips northwest at an angle of 50 degrees and has been mined 
to a depth of 280 feet. About 11,000 tons of rock are annually quarried. 
The gypsum is covered by twelve feet of blue clay and soil, and the salt 
formation is found at a depth of 200 feet. 

These eastern and central United States deposits belong to the earlier 
part of the Paleozoic era of geological time. Tn the western part of the 
country the deposits of gypsum belong to the closing part of the Paleozoic 
and to the Mesozoic time. 

§ 17. Iowa. 1 

The gypsum deposits of commercial value in Towa are found in Web- 
ster county in the north central portion of the state, in the vicinity of 
Fort Dodge. The area underlain by gypsum is given by Wilder, as 60 
to 75 square miles with at least 40 square miles available for working. 
The gypsum area is cut in two by the Des Moines river and large quan- 
tities of the gypsum have been removed through erosion. It is estimated 
that the total amount of gypsum removed up to the present time by 
mining is about twenty-five acres. 

These gypsum deposits were first described by Owen in 1S52 and later 
by Worthen and others. The first mill was erected in 1872 near Fort 
Dodge, and in 1878 the manufacture of hard wall plaster was com- 
menced. Other mills were erected later and now seven gypsum mills 
are located in this area with a total capacity of 000 tons of plaster a day. 

The gypsum rests on the St. Louis limestone or on the Coal Measure 
shales. Except near the streams the deposit is covered with drift. The 
gypsum is regularly stratified in heavy layers ranging from six inches 
to two feet and separated by thin layers of clay. Tn thickness the 
deposit varies from ten to thirty feet. The lower three feet of the series 
are usually rejected as impure, but the amount of such impurity is not 
great. The rock is crystalline throughout and its upper surface is quite 
irregular through water erosion. In composition the rock runs 09 per 
cent pure in the upper layers. 

The gypsum is overlain by red shales conformably, and both lie uncon- 
formably on the Coal Measures. The shales are without fossils. The 
age is given as Permian and the deposit was formed probably in an 
inland sea connected with the open ocean similar to the Mediterranean 
sea of the present time. 

In the earlier days of the gypsum industry of Iowa, the gypsum w r as 
obtained by stripping off the drift cover, one to twenty feet thick, and 
then quarrying out the rock. At the present time it is obtained by drift- 
ing into the deposit along streams or by shafts. Two or three feet are 
left for a roof and the entries are about nine feet high. The rock is 
calcined in kettles holding eight or ten tons each. 

1 Iowa Geological Survey, Volumes III, XII. 


§ 18. Kansas. 1 

The Kansas gypsum deposits of economic importance form a belt trend- 
ing northeast to southwest across the state. The belt of exposed rock 
varies in width from five miles at the north to twenty-five miles in the 
central part, and 140 miles near the southern line, with a length of 230 

This area is naturally divided into three districts, from which the 
important centers of manufacture are named : the northern or Blue Rap- 
ids area in Marshall county ; the central of Gypsum City area, in Dickin- 
son and Saline counties: and the southern or Medicine Lodge area, in 
Barber and Comanche counties. 

All of these deposits are found in the Permian, the central deposits 
are at the base of the Upper Permian, and the southern deposits are at 
the top of the Upper Permian, in the Red Beds. 

Gypsum of economic importance is found in two forms in Kansas, rock 
and gypsum earth. The rock is quarried especially in the northern and 
southern areas. It has a compact or sugary texture breaking with irreg- 
ular fracture, and usually white in color or slightly mottled through the 
presence of clay impurities. The rock in the northern area is eight and 
one-half to nine feet thick resting on a limestone floor and covered by 
shales. It is mined through tunnels driven into the hill, though formerly 
obtained by stripping. 

In the central area two companies are mining the gypsum rock through 
vertical shafts eighty feet deep which reach a 14 to 16 foot stratum. In 
the southern or Medicine Lodge area, the gypsum reaches its greatest 
thickness. It here caps the red clay and shale hills as a white rock layer 
protecting the underlying softer rock and gives a very picturesque topog- 
raphy in the Gypsum Hills country which continues southward into 
Oklahoma. The base of the hills is a massive red sandstone and above 
this are 200 feet or more of red shales, clays and some sandstone. At the 
top is a gypsum layer three to forty feet in thickness. 

TUe gypsum earth deposits are found especially in the central area and 
were the first deposits of this kind worked in the United States. They 
are described in another chapter. 

At the present time there are three gypsum mills in the northern area 
which are working the rock. In the central area there are four mills, two 
using the rock and one using the gypsum earth and one using both rock 
and earth. In the southern area there are two rock mills. Very little 
Kansas gypsum is ground for fertilizer, but most is calcined into plaster 
of Paris or cement wall plaster. The method of manufacture in these 
mills is practically the same as used in Michigan and the plaster is 
calcined in kettles. Of the nine mills, four are owned by the United 

>University Geological Survey, Vol. V. 


States Gypsum Co., two by the American Cement Plaster Co., and three 
by separate companies. 

§ 19. Arkansas. 1 (Plate XXIX, location 11.) 

At Plaster Bluffs on Little Missouri river in Pike county, and at many 
other points along the southern boundary of the Trinity formation, there 
are beds of gypsum and gypsiferous marls of all degrees of purity and 
excellence, from pure saccharoidal gypsum to that containing from 10 
to 20 per cent of gypsum in quantities practically inexhaustible. 

The gypsum occurs in strata six inches to six feet in thickness with 
seams of satin spar, 10 feet in all overlain by 15 feet of gypsiferous sands 
and marls and 50 feet of Quaternary gravels. The gypsum rests on a 
sandy lime stratum one foot thick, and below this comes sands, shales, 
and marls. The gypsum is suitable for the manufacture of plaster of 
Paris, and the impure gypsiferous marls might be used for fertilizer. At 
the present time no use is made of this material. 

§ 20. Oklahoma. (Plate XXIX, location 15.) 

The extensive gypsum deposits of Oklahoma are of Permian age and 
they are grouped by Gould in his report published by the Oklahoma Sur- 
vey under four general regions : 

1. The Kay county region in the central part of Kay county. 

2. The main line of the Gypsum Hills extending from Canadian county 
northwest through Kingfisher, Ulaine, Woods, and Woodward counties 
to the Kansas line. 

3. The second Gypsum Hills extending along a line parallel with the 
main range and from 50 to 75 miles further southwest, from the Keechi 
Hills in southeastern Caddo county, northwest through Washita, Custer, 
and Dewey counties into Woodward and Day counties. 

4. The Greer county region occupying the greater part of western 
Greer county as well as the extreme southeastern corner of Roger Mills 

In the first region are small deposits of gypsum earth and one plaster 
mill is located there. In the second, which is the same as the Medicine 
Lodge Hills in Kansas, the gypsum ledges aggregate 60 to 90 feet in 

In this area is the Okarche mill using secondary gypsum and it is the 
oldest gypsum mill in the territory. The features of topography and re- 
lations of the gypsum to the red shales and clays are the same as in the 
southern Kansas area, 

The third area is to the west of the main line of the Gypsum Hills and 
at a higher geological level. The formations in this range of hills ex- 
tend from Woodward county to Comanche and run nearly parallel to 

'Arkansas Geological Surrey Vol 1, pp. 119, 241, 267 : 1888. 


the range of hills forming the second area, and 25 to 50 miles west. The 
gypsum in these hills is not usually found in continuous ledges. A 
single ledge will in a short distance appear in several ledges. Gypsum 
ledges run a short distance and then disappear. 

Instead of the gypsum capping ledges and making steep hills as in the 
preceding area, it appears on the surface in the form of rounded knolls or 
mounds. The width of the gypsum outcrops east and west varies from a 
few miles to thirty. The thickness runs from 10 to 50 feet, and the rock 
is about 93 per cent pure. 

In the fourth or Greer county area, the gypsum seems to be at about 
the same geological level as in the third area. In Greer and Roger Mills 
counties, there are five well marked gypsum ledges. Along the north 
fork of the Red River in Roger Mills county, the bluff runs for 10 miles, 
150 to 200 feet high, and is composed of red clay with four ledges of mas- 
sive white gypsum, which will reach a total thickness of 70 feet. 

There are extensive deposits of gypsum in Greer county which appear 
in ledges in ravines in the northern part of the county, but the gypsum 
appears at the surface in very few places in the level country of the 
southern part of this county. Mr. Gould has estimated the area of 
gypsum in this region to be 050 square miles with a thickness of 35 
to 50 feet. He further estimates the quantity of gypsum in Oklahoma 
to be 125,800,000,000 tons. 

There are four gypsum mills in operation in Oklahoma. The Ruby 
Stucco Plaster Co. mill is located in north central Blaine county four 
miles west of Ferguson. The hill near the mill shows three ledges of 
gypsum with a thickness of 35 feet. The mill was erected in 1001 and 
has a daily capacity of 150 tons. 

The American Cement Plaster Co. mill is located at Watonga in 
Blaine county and the rock is hauled three miles by rail to the mill 
which has a daily capacity of 75 tons. 

The Okarche mill near Okarche uses the secondary gypsum earth. The 
Black well Cement Co. mill is near Peckham in Kay county and was 
built in 1899, and has a daily capacity of 100 tons made from the gypsum 

§ 21. Texas. (Plate XXIX, location 16.) 

The first account of the gypsum deposits in Texas is probably to be 
found in Marcy's Red River Report of 1852 1 in which he states that near 
the source of that river the waters had a peculiar taste, received in 
flowing for 100 miles over a gypsum formation, which he described as 
follows : 

"I have traced this gypsum belt from the Canadian river in a south- 
west direction to near the Rio Grande in New Mexico. It is about fifty 

iPagesi?, 91, m, 173. "" 


miles wide on the Canadian, and is embraced within the 99° and 100° 
meridians of west longitude. Wherever I have met with this gypsum I 
have observed all the varieties from common plaster of Paris to pure 
selenite. I regard this gypsum belt as a very prominent and striking 
feature in the geology of the country. From its uniformity and extent, 
I do not think there is a more perfect and beautiful formation of the 
kind known. I have myself traced it about 350 miles, and it probably 
extends much farther . . . The only deposits known to me as more 
extensive are those in South America, described by Darwin in his geology 
of South America. Very probably the ancient igneous agency in the 
Wichita mountains, and along a line southerly to the Rio Grande may 
have been concerned with the production of the gypseous deposit of the 
same region." 

In Texas. Dumble 1 reports valuable gypsum deposits in the lower 
Comanche series of Burnet county. In the Permian the beds are numer- 
ous and often of considerable thickness. The clay is traversed in every 
direction by seams of fibrous gypsum, varying in thickness from paper 
like seams to 10 feet, while the compact gypsum reaches 25 feet. 

The valuable deposits of northern and western Texas, Dumble be- 
lieves were deposited in an arm of the sea cut off from the old Permian 
ocean. The rock is used for plaster of Paris, wall plaster, and fertilizer. 
The fertility of the river valleys is regarded as due in part to the fact 
that the rivers have their sources in the gypsum beds. 

The plaster industry of Texas at the present time centers in the region 
around Quanah in the northern part of the state. Both rock and earth 
are found here, but the earth deposits are the ones usually worked. 
The first company to locate in this area was the Acme Cement Plaster 
Co., of St. Louis. They have eight eight-foot kettles producing about 
300 tons of plaster daily and manufacture all grades of plaster, including 
plaster of Paris, wall plaster, and Keene's cement. They use earth and 
rock in their work. The American Cement Plaster Co., of Kansas, also 
has a mill in this section which is using the gypsum earth. The earth 
deposits near Quanah are said to cover nearly a thousand acres. 

• § 22. Colorado. 2 

The important gypsum producing center in Colorado is in Laramie 
county where there is one mill located five miles west of Loveland. The 
gypsum stratum is found in a valley of erosion one-half mile wide in 
the midst of mountain folds of Jura-Trias age, and the basin is hollowed 
out of an anticlinal fold. The main quarry shows a gypsum face 250 
feet long, 28 feet high at the center, and sloping to 7 feet at the edges. 
The gypsum is compact, gray in color, over 99 per cent pure, and is found 
in two beds, one over the other, having a dip of 15 degrees to the north. 

iFlrst Annual Report, pp. 128, 188, 198: Second Report, pp. 465, 456, 70a 
tLftkes in Mine* and Minerals. Vol. 20, p. 227 ; 1890. 
Lee in 8 lone, VoL 21, July, 1900. 


The cover is not over 18 feet, and the gypsum rests on a variegated 
chocolate limestone. 

The deposit is owned and worked by the Consolidated Plaster Co. 
Their mill has a capacity of 40 tons in 10 hours and uses six ton kettles. 
They manufacture plaster of Paris, dental plaster, and cement wall 

§ 23. Wyoming. 1 (riate XXIX, location 17.) 

There are a number of gypsum deposits in Wyoming, varying in com- 
position from pure crystal to earth gypsum. At Red Buttes plaster of 
Paris and wall plaster of fine quality have been made since 1889. The 
Consolidated Company has been engaged in the work at this place since 

Oypaum Deposit* 

Figure 7. Geological section of Wyoming gypsum deposit. 

A second locality of plaster manufacture is near Laramie, where a 
deposit of 180 acres of secondary gypsum is worked by the Standard 
Cement Plaster Co., now owned by the Acme Cement Plaster Co., of St. 
Louis. This plant was erected in 1896. 

The gypsum in Wyoming occurs in the "Red Beds" of the Triassic 
formation. The thickest stratum is near the bottom of the formation 
above the sandstone and limestone of the Permian and Carboniferous. 
(See Figure 7.) 

The Red Buttes gypsum is in the same formation and the gypsum out- 
crop may be found at a number of places along the eastern side of the 
Laramie Plains within a half mile of the limestone and sandstone ex- 
posures which form the western slope of the Laramie Mountains. 

The sand and lime have washed down from these exposures and are 
mixed with disintegrated gypsum and deposited in depressions of the 
plains forming numerous beds of gypsum earth. 

The Laramie secondary gypsum has an average depth of 9 feet, 7 
feet of this is pure gypsite resting on a five inch red layer and below 
this is a foot or more of white gypsum earth resting on gravel and red 
clay. This gypsum earth used in the manufacture of plaster is very 

fine in texture and is scraped up and calcined in five ton kettles in about 


•Slosson In Agricultural College Report for 1900. 
Knight in personal letter. 





























three hours. The earth has a small proportion of soda in it which is 
thought to make a stronger plaster. 

§ 24. Nevada. 1 (Plate XXIX, locations 25 and 26.) 

In northwestern Nevada there are two localities where gypsum is 
found in large quantities. One is in the Virginia, and the other in the 
Humboldt range of mountains. 

The Virginia range runs north and south some eight to sixteen miles 
east of the California-Nevada boundary. It is composed throughout the 
greater "part of its extent of Cenozoic volcanics. South of Virginia 
City the older rocks of the "Bed rock" series are exposed. This series 
consists mainly of granitoid rocks with disconnected included masses 
of older strata much metamorphosed. In one of Ihese areas of meta- 
morphic rocks, six and one-half miles south of Virginia City on the 
Virginia and Truckee railroad is a mass of gypsum which lies in a thick 
bed almost vertical, and is finely granular, white in color. The roof and 
floor are formed of light colored limestone. The greatest width or thick- 
ness of the gypsum along the surface is about 450 feet, the south side 
is abruptly cut off by diorite rock. 

The gypsum mass runs north for 200 yards with its maximum thick- 
ness, then it narrows down and is continued north for half a mile in 
disconnected lenses. The gypsum through erosion now rests in a de- 
pression and much of it has been washed down an eastward ravine where 
it is mixed with earth forming gypsiferous alluvial deposits. 

The rock is removed from cuts on the west side and hauled to Empire 
on the Carson river, where it is calcined. The rock contains over 90 per 
cent gypsum, with a considerable amount of lime carbonate. 

In origin, the gypsum is thought to be an original part of the strati- 
graphic series of limestones and quartzites, and formed by precipita- 
tion from saline w r ater. All the evidence at hand seems to be opposed 
to an origin of gypsum through the alteration of the limestone. 

In age the gypsum belongs to the series of older rocks that were in- 
truded and folded at the time of the post- Jurassic upheaval of the moun- 
tains and is unconformable below the Tertiary lavas. The gypsum 
is either Triassic or Jurassic and probably the former. 

Lovelock Deposit (Loc. 25.) 

The Humboldt mountains form a range about the middle part of 
northwestern Nevada, 80 to 90 miles east of the California-Nevada 
boundary. In the southern or Humboldt Lake group of these mountains 
is found the Lovelock gypsum deposit. The rocks of this range are 
divided into the Bed rock and the Superadjacent series. The^foitaxr 
consists of Trias and Jurassic sediments iwidetrt^tnnM^ttfiWpWSed, 

'From notes furnished by Dr. IxmdeWifc^ta^fclVS^ «f**WV&«*P<I9->q ew iau ,°??« * ,riT ' ^ 
_ ' . IW I .8 emit ,83 


folded, and faulted. These are overlaid unconformably by the Superadja- 
cent series made up of Cenozoic volcanics. 

The gypsum deposit lies on the west flank of the northern part of the 
Humboldt Lake range interstratified in the sedimentary series, some 
six miles northeast of the town of Lovelock on the Central Pacific rail- 
road. The deposit is mainly a grayish white granular mass of rock and 
quite free from foreign substances. 

The gypsum rock forms the axis of an anticline and is exposed for some 
three-quarters of a mile, pitching below the surface to the north and 
south. Further north it is brought to the surface again by faulting 
in the form of a low syncline. The two branches of its exposed surface 
can be traced to the Humboldt valley, one-half mile along one exposure, 
and one mile along the other. The roof is a granular white limestone 
followed by a black limestone which is fractured and intersected by 
numerous veinlets of calcite. The floor is a white limestone, and layers 
of limestone occur through the mass. 

The deposit of gypsum is a stratum of the Bed rock series, and all evi- 
dence seems to show it is an original deposit from some arm of the sea 
and is probably middle Triassic in age. Chemically the rock contains 
95 to 98 per cent of gypsum. 

The gypsum was opened in quarry some years ago and then abandoned 
on account of the expense of transportation. Recently a company has 
been organized to develop the Lovelock gypsum and ship it into Cali- 

§ 25. California. 1 (Plate XXIX, locations 28, 29, 30.) 

The grinding of gypsum rock into land plaster for fertilizing purposes 
has been carried on at a number of places in California, where deposits 
of varying thickness and quality have been opened. In 1892, and for 
some years afterward, land plaster was made at Coalinga from a ten 
foot stratum and the plaster was used to a considerable extent in the 
rich fruit belt at Tulare and Fresno counties. In various parts of Los 
Angeles, Riverside and Santa Barbara counties, gypsum deposits in 
Tertiary clays have been used for land plaster. 

The manufacture of plaster of Paris in the state in the past seems, 
in many cases, to have resulted in failure of the companies engaged in 
the work, partly on account of the selection of the poor quality of rock, 
and partly on account of the lack of skilled calciners. While there are 
large deposits of gypsum rock found at numerous places north and 
south, through the Sierra Nevada and Coast Range mountains, most of 
the material so far tested seems to be too impure for plaster of Paris, 
making a dark plaster. 

The pioneer in the plaster of Paris industry in California was Mr. 

'This account was prepared by the writer for the Eng. & Mln. Journal and published in Vol. 71, No. 
28, June 8, 1901. 


John Lucas, who came to the state in 1865, after a number of years 
experience as calciner for the Phoenix Plaster Co. of New York City, 
one of the leading old time companies. Mr. Lucas experimented with 
various deposits of gypsum and finally selected a deposit near San Luis 
Obispo, the rock from which was brought to San Francisco and burned 
in an ordinary gypsum kettle into the so called Golden Gate plaster of 
Paris. The business was continued by his sons until about a year ago, 
when the mill was burned. Of late years the gypsum rock* was shipped 
from San Marcos Island in the Gulf of California, nearly 1,500 miles 
away. This island is 7 miles long and 3 miles wide, with 280 feet of gyp- 
sum exposed over a large portion of it. The rock is a cream white in 
color, compact, of a high degree of purity and makes an excellent plaster. 

Gypsum cement plaster is made near Los Angeles at Palmdale, 62 
miles from Los Angeles, where the Alpine Plaster Co. has been engaged 
in this line of work for 15 years. The company owns a deposit of 240 
acres, which has been worked to a depth of 10 and 20 feet and averages 
95 per cent gypsum. The finished plaster is faster setting than eastern 
plasters, reaching its set in 45 minutes. Another company known as 
the Fire Pulp Plaster Co., of Los Angeles, is engaged in the manufac- 
ture of a special kind of wall plaster made by mixing plaster of Paris 
with clay and asbestos fibre, so as to combine fire proof qualities, slow 
set, and durability. The company is now constructing their own calcin- 
ing plant. 

On account of the mild climate in California, gypsum plasters can 
be used for outside work as well as on interior walls. Some of the 
earlier attempts at the manufacture of hard plasters proved to be failures. 
Such failures have retarded the introduction of these plasters in this 
State, and there has been a strong prejudice in favor of ordinary lime 
plasters. The larger buildings are now plastered with hard plasters, 
and this industry is attracting much attention from eastern plaster men. 
The manufacture of hard gypsum plasters will without doubt be a very 
important industry in California in the next few years. 

§ 26. Other Districts. 

Gypsum deposits are found in several other states and territories in 
the western part of the United States. The Oregon Plaster Co. operated 
a small gypsum mill near Huntington, Oregon, for a number of years, 
and it is reported that the plant has recently been sold to the United 
States Gypsum Co. (Location 24.) 

In Utah deposits are described at a number of places to the south 
and south-west of Salt Lake. The Nephi Plaster and Manufacturing Co. 
operated a mill at Nephi. In New Mexico the gypsum is said to occur 
in very large areas, and both rock and gypsum earth are found. A mill 
is in operation near the southern part of the territory. 


In the Black Hills of South Dakota the Sturgis Plaster and Stucco 
Co. have operated a small mill, and Mr. Powers of Grand Rapids, Michi- 
gan, built a small mill in this same region. (Location 31.) 


§ 27. Earthy Gypsum, Distribution of. 

In the State of Michigan, gypsum is found only in the rock form, 
and no deposits of earthy gypsum of economic importance are known to 
exist. Such deposits have been described in Europe: in Germany under 
the name of Gypserde, Himmels' mehl ; in Sweden, as Himmels mjol ; 
in Russia, Gipsowaya muka. These deposits are loose, dust like particles 
of yellow or gray color, and are found in Saxony near Neustadt, in 
Bohemia near Frankenhausen, also in Norway, and near Paris. Its 
origin in these regions is ascribed to the solution of gypsum in water, 
and it is more abundant in wet than in dry seasons. At Frankenhausen 
it was observed on the top of a gypsum mountain, as a superficial stratum 
of about one and a half feet thickness, unconsolidated, and still contain- 
ing water. Its main use in these areas is a fertilizer and as. white-wash. 

In the United States gypsum earth is found and worked at a number 
of localities west of the Mississippi river. The plaster made from such 
material is darker in color than that made from the gypsum rock, but 
it is held in high favor by the plasterers in those sections, and by many 
it is regarded as more desirable. 

Deposits of gypsum earth are now worked in Kansas, Oklahoma, 
Texas, and Wyoming. The material is locally called "stucco," "gypsum 
earth," and "gypsite." It is a granular earth found often in low swampy 
ground, dark colored in place, but on drying it assumes a light ash- 
gray color. It is soft, incoherent, so that it is readily shoveled into cars, 
and it is ready for calcining with. less labor and expense than is required 
in working the solid rock. 

§ 28. Kansas. 

The first deposits of this earth were worked in Kansas, where the 
material was discovered in the spring of 1873 near Gypsum City in the 
central part of the state. In 1880 the Saline County Plaster Co. was 
organized and built a mill to calcine this material. The property was 
afterwards sold to the Acme Cement Plaster Co., which soon became 
prominent in developing this and other deposits in the southwest. The 
Gypsum City mill furnished 7,000 tons of plaster made from gypsum 
earth for the World's Fair buildings at Chicago. The deposit covers 
an area of 12 acres, and lies close to the surface with little or no cover, 
and it is in a small creek valley. The maximum thickness of the earth 
is 17 feet with an average of 8 feet. Strong springs break through the 
deposit on the east side, and the top of the earth is 20 feet above the 


water in the creek. Rock gypsum is found in borings 20 feet below the 
top of the earth, but there is no trace of gypsum rock above. 

The Agatite earth deposit near Dillon and 14 miles east of the last 
locality covered 40 acres in a swampy area near another small creek. 
Its greatest thickness is 18 feet and the earth is covered to a slight depth 
with soil. Gypsum rock outcrops at the same level a quarter of a mile 
away. This deposit has been abandoned, and the mill moved to Texas. 

Another deposit is worked to the south of Dillon varying in depth 
from 2 to 8 feet, and gypsum rock is found above and below it. Near the 
bottom of this gypsum earth, in this deposit and another further south, 
recent shells and bones have been found. Seven miles south of the 
Agatite deposit another area was worked for a number of years and was 
similar in its characters to the other deposits of this area. An area of 
about 60 acres of gypsum earth was discovered and worked in north 
central Kansas at Longford in Clay county, and in south central part 
of the state at Burns and Mulvane two deposits were opened. 

The Kansas gypsum earth deposits are found in low swampy ground 
■ associated with water. They have a limited surface extent and depth. 
At the present time only three mills are calcining this material, and one 
of these uses rock gypsum with the earth. 

§ 20. Oklahoma and Indian Territory. 

The deposits of gypsum earth as well as gypsum rock are wide spread 
in Oklahoma and they have attracted much attention. The various new 
lines of railroad have disclosed their presence and have given the oppor- 
tunity for their development. While the deposits are large, the amount 
of manufactured product is small at the present time. 

A small mill was in operation for a number of years at Marlow, Indian 
Territory, but the deposit of earth at this point was small and the mill 
has been abandoned. 

At Okarche, Oklahoma, the Oklahoma Cement Plaster Co. has the old- 
est mill in the Territory. It is a two kettled frame mill with a capacity 
of 80 tons of plaster a day, sold under the name of O. K. They began 
their work on a three-acre gray earth deposit which was three feet in 
thickness resting on three feet of red earth. The company owns a number 
of these small deposits within a few miles of the mill. One and one- 
half miles west of the mill are two deposits, 13 and 40 acres in extent, 
and of a variable thickness. 

Chemical analysis shows the gray earth to be much purer than the red 
earth below. 


0. K. 
















38 OYP8UM. 



Insoluble matter 7.98 

Iron oxide 0.27 

Alumina oxide 0.23 

Magnesia carbonate 0.24 

Lime sulphate 71.70 

Water 18.08 

Carbonic oxide 1.14 

Total 100.24 100.15 97.46 

Ten miles west of Okarche on the north bank of the Canadian river, 
are extensive deposits of gypsum earth distributed over an area of 200 
acres ranging in depth from 6 to 20 feet. 

The only other mill in Oklahoma using gypsum earth is the Kay county 
mill owned by the Blackwell Cement Co. It is a two kettle mill with 
a capacity of 100 tons a day. 

§ 30. Texas (location 16 and 33). 

In the northern part of Texas, near Quanah and Acme on the Denver 
and Fort Worth railroad, are very extensive deposits of gypsum earth 
reported as the largest in the United States. These are now worked by 
the Acme Cement Plaster Co., and by the American Cement Plaster Co. 

§ 31. Wyoming. 1 

One of the members of the company which developed the Dillon, Kansas 
gypsum earth deposit, discovered similar deposits near Laramie, Wyom- 
ing, and in 1896 organized the Laramie Cement Plaster Co., which erected 
a 150 ton mill (location 17). 

The gynsum earth has an average depth of 9 feet, 7 of which are 
worked. The deposits are found in depressions in the Triassic sand- 
stone. These rocks outcrop for a distance of over 50 miles along the west 
flank of the Laramie mountains and the gypsum deposits are known to 
exist for over one-half of this distance. 

According to Prof. Knight, the gypsum earth has come from beds 
of gypsum, limestone, and sandstone, that lie higher up along the slope 
of the mountains. The composition of the earth is shown by the follow- 
ing analysis: 

UOtta Annual Report of University of Wyoming, pp. 1-18 : 1900. 
Also letter to writer from Prof. Wilbur Knight. 


Laramie earth. Red Buttes earth. 

Lime sulphate 70.08 64.22 

Lime carbonate 8.36 15.74 

Silica 5.62 4.50 

Iron oxide and alumina 0.64 1.26 

Water 8.88 14.00 

Sodium sulphate 3.25 

Magnesium sulphate 3.72 

Total 99.55 99.73 

§ 32. Microscopical Examination of Gypsum Earth. 

Under the microscope the gypsum earth shows considerable uniform- 
ity in character, as shown in Figure 31. The earth is seen to consist 
of a mass of small, angular gypsum crystals of varying size. Perfect 
crystals are found, but most of the crystals have the terminations some- 
what rounded by solution. They are not transported crystals, but they 
have clearly crystallized in place. Mingled with the gypsum crystals are 
often small quartz crystals. A considerable amount of poorly crystal- ' 
lized calcite is present, and also traces of organic material. 

§ 33. Chemistry of Gypsum Earth. 

South of Dillon, Kansas, at the works of the Etna Cement Plaster Co. 
the rock and gypsum earth are both found and show the following com- 
position : 

Rock. Earth. 

Silica and insoluble matter 1.18 3.18 

Iron and aluminum oxides 0.15 0.95 

Magnesium carbonate 0.52 0.33 

Calcium carbonate 0.36 6.18 

Calcium sulphate 78.04 69.70 

Water 20.00 19.44 

Total 100.25 99.78 

A comparison of these analyses shows that the earthy variety contains 
more impurities, as silica, iron, and alumina, and lime carbonate, and 
a lower percentage of calcium sulphate, than the rock gypsum. 

In the Medicine Lodge Valley in Kansas, the rock gypsum 10 to 20 feet 
in thickness is covered near Springvale by a deposit of red gypsum earth. 
Between the two, is a porous, fibrous, brittle, white gypsum, evidently 
due to the alteration of the white compact rock below. Samples of these 
were collected and analyzed for the writer at the University of Kansas, 
under the direction of Prof. E. H. S. Bailey. 


Solid Porous Red 
rock. rock, earth. 

Silica and insoluble matter 0.29 0.36 41.74 

Iron and aluminum oxides 0.27 0.30 7.36 

Magnesium carbonate 1.00 0.82 3.09 

Calcium carbonate 13.04 6.89 9.21 

Calcium sulphate 71.58 73.35 29.32 

Water 18.46 19.38 9.32 

Total 104.64 101.10 100.04 

The leaching action has removed much of the lime carbonate and evi- 
dently part of the magnesia carbonate. The analysis of the earth shows 
it to be a clay in which the gypsum has been deposited and would per- 
haps be defined as a gypsiferous clay or shale. 

These deposits of gypsum earth generally show r higher percentages of 
the soluble constituents than the rock variety, and a lower percentage 
of lime sulphate. They are usually higher in silica and insoluble matter. 

§ 34. Origin of the Gypsum Earth Deposits. 

Gypsum in a form resembling satin spar and in an earthy form is 
deposited at the present time in dry weather to the extent of nearly one- 
half inch in a few days by the evaporation of running water along chan- 
nels near these places. Where the gypsum water of the springs in these 
deposits is evaporated there remains a crust of gray earthy gypsum 
resembling very closely the gypsum earth. In Oklahoma I have found 
stalactites hanging from under a ledge of this earth and clearly formed 
by precipitation from water, also crusts of the earth in wavy form on 
the surface of the earth deposit and even on the surface of rock gypsum. 
By a laboratory experiment with an artifical spring, I have secured 
material as a deposit from the evaporated water similar to these earths. 
In this spring arrangement, I placed layers of limestone crushed, clay, 
and ground gypsum rock and allowed the water to rise from below 
through the mass. This water flowed into a basin and evaporated slowly 
in the heat of the room. 

A study of the analyses already given shows that the amounts of silica, 
alumina, and lime carbonate, in the earth deposits are higher than in 
the rock, which would be expected in a secondary deposit formed in a 
swamp. The amount of sulphate of lime is lower, so that the earth is 
not as pure as the rock. The impurity of the earth makes it set more 
slowly, and so requires less retarder to be added. 

The microscopical crystals in this earth are angular and many of 
them perfect. No masses of gypsum rock are found in the earth, and no 
fragments of other stone or sand in any amount. The material is quite 
uniform in size and chemical composition through the whole deposit. 
If the material was washed from gypsum rocks of higher levels, as some 


have maintained, some fragments of gypsum and other rock would cer- 
tainly be found in some of these deposits. 

Spring Theory of Origin. 

This theory of origin was first published by the writer in the Kansas 
report on gypsum. The gypsum earth, then, must have been deposited 
in these places from solution. If from solution in surface streams, con- 
siderable sand and silt would have been carried in, and the chemical 
composition would vary in different parts of the mass. Further as in 
most of these areas, no gypsum is over the earth, the streams would have 
to bring the gypsum from long distances. Some sand, clay, lime car- 
bonate, and organic material are shown by chemical analyses and by 
the microscope, and these may be due to surface agencies. The water 
circulating through or near the underlying gypsum rock dissolved a por- 
tion of the rock and carried it upward in the springs to the surface of 
the swamp, where the material was precipitated through evaporation 
aided by the action of organic matter of the decaying vegetation. 

A crust of gypsum would thus be formed and would increase in thick- 
ness until all the underlying rock was removed. Now, in some of these 
deposits borings detect no gypsum below the deposits, but it is found in 
wells outside at a level below the earth. In such places probably all the 
gypsum rock adjacent to the gypsum earth area has been removed by 
solution. Again by building up the swamp floor to a certain height, the 
rise of the gypsum water springs may have been checked so as to hinder 
the earth formation. Whatever the cause, the gypsum earth deposit is 
not now forming over the entire area in any appreciable amount. 

The uneven thickness of the deposits, some varying from three to eight 
feet within the main part of the deposit, shows that the conditions were 
more favorable at certain points than at others. Possibly these thicker 
portions were nearer the outlet of stronger springs. 

The deposits were formed in a comparatively short period of time. The 
presence of modern fresh water shells shows that the deposits are recent, 
formed long after the rock gypsum in the same region. 



§ 1. Early Reports'. 

In 1825 a mission was started near the present site of the city of Grand 
Rapids by Rev. Mr. Slater, on the west bank of the river known by the 
Indians as the Wushtenong (the further district) and called by the 
whites the Grand river. 

In 1827, when General Cass was Governor of the northern territory, 
an Indian trapper brought to the Slater mission a piece of soft white 
rock which proved to be gypsum. It had been found near the mouth 
of Plaster creek, where the existence of such rock was known to the 
fur traders, but this specimen seemed to be without value, and it was 
not worked for 14 years after this date. 

In 1838, Dr. Douglass Houghton, 1 the State Geologist, was called to 
Grand Rapids to select a location for a salt well, and in his report de- 
scribed the plaster beds as follows : 

"Near Grand Rapids, in Kent county, a bed of gypsum occurs appar- 
ently of considerable extent. It is embraced in a gypseous marl, and 
overlays the limestone before noticed as occurring in this neighborhood. 
Although the gypsum is only seen upon the surface at two or three 
points, and the beds have never been opened, I am satisfied, after a 
somewhat cursory examination, that it exists, covered with a few feet 
of soil over a considerable district of country, and that it cannot fail 
to prove a subject of much value to the agricultural interests of this 
and adjoining parts of the State. 

"The gypsum is of the fibrous variety, nearly free from earthy matter, 
and it is well adapted to nearly all the uses to which this valuable min- 
eral is applied. The bed is distinctly stratified, the layers varying from 
12 to 15 inches in thickness, and they are separated from each other by 
argillaceous matter and earthy gypsum. 

"Plaster is also known to exist at several other points in our State, 
but sufficient examinations have not yet been made to throw any light 
upon the probable extent of the beds." 

As far as can be determined from the old records, Mr. James Clark 
was the first man to calcine Michigan gypsum. This man, described as 
an energetic, enterprising, upright man, came from New Jersey as a 

1 Report of State Geologist, p. 11: 1838. 


member of the fourteenth white family to Grand Rapids in 1834 and 
followed his trade as a plasterer. In building a house for that famous 
early trader of this region, Louis Campau, he wished to add some orna- 
mental stucco mouldings which were to be placed in the gables and 
around some circular windows. Mr. Clark had heard of the Plaster 
creek gypsum and secured some of it, which he broke into small pieces 
with a hammer and had it ground in an old Indian corn mill and then 
burned the material in a cauldron kettle. On the first attempt at con- 
structing the ornaments the stucco dropped to the ground, but a second 
attempt was successful and the mouldings remained until the house 
was destroyed by fire in 1850. 

The first inside mouldings and center piece ornaments of plaster were 
made in a house on the corner of Bronson and Ottawa streets in Grand 
Rapids by Philip Stewart. In 1845 Daniel Prindle, a man well re- 
membered for his good work and blunt manner of speech, commenced 
in a small way the manufacture of plaster flower pots and other utensils. 
Mr. Prindle's work soon changed to the manufacture and setting of 
inside ornamental work, and in the house of Mr. Rumsey, built 45 years 
ago, some beautiful pieces of his work still stand firm and fresh. 

Plate I gives photographs of some of these pioneers in the industry. 

From 1837 to 1841 the gypsum rock was brought from Plaster creek 
and ground on a small scale in corn mills. The ledge was six inches 
to eight feet in thickness, and is now seen to be the upper stratum of 
the Grand Rapids gypsum. 

In 1840 Dr. Houghton 1 again called public attention to these deposits, 
and pointed out the importance of their development in the following 
words : 

"Closely connected with the iron ores of our State in importance, is 
the subject of calcareous manures. Our citizens are already annually 
importing from the neighboring states, large quantities of plaster, and 
this import must have a rapid increase unless means be taken to open 
the stores which are found within our own State. There is no point now 
known where gypsum can so readily be obtained, and where it is at the 
same time so advantageously situated for distribution over the sur- 
rounding country, as at the Rapids of the Grand river. Here is an 
extensive deposit of this important mineral, which in quality is not ex- 
ceeded by any in our Union, yet thus far it has been entirely neglected. 
This should not be, for the time has now arrived when it is required for 
use, and no contingency should be allowed to arise that will cause it any 
longer to lie dormant." 

§ 2. History of the Grand Rapids District South of the River. 
In the next year, 1841, the first mill was erected for working the 
gypsum deposits, by Warren Granger and Daniel Ball near the place 

> Report of State Geologist for 1840. 


where Plaster creek crosses the Grandville road. The land was owned 
by Mr. Degarnio Jones of Detroit, who had secured 80 acres of this 
land before 1838, and these men paid Jones rent in plaster delivered by 
water at Detroit. The mill was equipped with crude grinding apparatus 
and one run of stone operated by water power from the creek, and with a 
two barrel cauldron kettle with thick bottom. Under Mr. Rumsey's 
management, the next year, three cauldron kettles were set in an arch 
and fired with dry wood. The plaster was stirred by means of a stick 
with a spud at one end and was removed by shovelling out to one side 
after the first settling. The manufacture of calcined plaster was a very 
small part of the work, as most of the rock was ground for land plaster. 
For this purpose the stone was broken with a hammer and passed 
through an Indian mill or crusher and ground betw r een mill stones. 
The land plaster was shipped down the river and around the lakes to 
Detroit, and from there sold to the neighboring territory. In order 
to call attention of the farmers of the vicinity to their work. Granger 
and Ball had posted, in conspicuous places, the following advertise- 


The subscribers have now completed their Plaster Mill on Plaster 
Creek, two miles south of this place which is now in operation. They 
respectfully inform the public that they have on hand at the mill or at 
either of their stores at Ionia or this place a constant supply. As the 
quality of the Grand Rapids Plaster is not equalled by any in the 
United States, they hope to receive a share of patronage as the price 
is less than it can be obtained for at any place in Michigan. Wheat, 
Pork, and most kinds of produce received in payment. 

Granger & Ball. 

Grand Rapids, December 21, 1841. 

The first week after the posting of this notice, 40 tons of plaster were 
sold at the mill at $4.00 per ton. In 1843, Ball sold his interest in the 
lease to Henry R. Williams, who was the first mayor of Grand Rapids. 
Mr. Williams started out in the winter with loads of plaster in a sleigh 
and traded it to the farmers for corn, and kept up this work until the 
farmers became familiar with use of plaster and soon the demand was 
beyond the supply and the price reached $ 5.50 a ton at the mill. In the 
winter of 1848-9 the mill was running night and day without equalling 
the demand, so that some teams coming 100 miles were forced to return 
without a load. In 1852, 60 tons of plaster were hauled every day south 
by teams, and that year the property passed into the hands of E. B. 
Morgan & Co., and later was bought by N. L. Avery & Co., the company 
including Sarell Wood and Benj. B. Church. They changed the water 
course and moved the mill across the road. This firm dissolved partner- 


ship in December, 1857, and was succeeded by Sarell Wood & Co., the 
company now including Barney Burton, who soon withdrew, and Chas. 
A. Todd and Abel Thompson took his place. 

In 1860, Freeman Godfrey built a mill near the mouth of Planter 
creek, three-quarters of a mile from the old mill described, and began 
the business of mining, manufacturing, and selling plaster. Mr. God- 
frey was born in Vermont, September 5th, 1825. He became a rail- 
road contractor in 1845, and, in December, 1856, came to Grand Rapids 
on the construction work of the Detroit and Milwaukee railroad, which 
was completed in 1858. He died in Grand Rapids in 181)7. 

In 1862 he took his brother Silas into partnership under the name of 
F. Godfrey and Brother. At this time Mr. Godfrey attempted to im- 
prove the method of calcining plaster by using two sets of three cyl- 
inders for calcining, one placed above the other in each set, all enclosed 
in brick work with one fire under all. The plaster was carried by means 
of a fixed screw on the in&ide of the cylinders from the upper one out 
to the end and dropped into a hopper and down into the middle cylinder, 
and out of the opposite end into the hopper of the lower cylinder, and then 
out of this over a screen into the cooler. He had tried two cylinders, one 
above the other, and in both groups of two and of six, the cylinders were 
slowly revolved by the aid of friction rolls on the outside. 

In his first attempt with the two cylinders, the lower one was sup- 
ported on rolls at one end and the other end was driven by a shaft 
which also operated the upper cylinder. He next changed the arrange- 
ment and belted the two together, but the resistance was so great that 
the belt would slip and the upper cylinder was not turned regularly. 
In both designs of these cylinders the plaster was not evenly calcined. 

The screen used was of perforated metal and the plaster passing 
through this fell into a double hopper, into the outer part of which water 
was forced by a plunger pump and came out of the top hot. Mr. 
Godfrey made his cylinders out of some old boilers which were about 
three feet in diameter and 16 to 18 feet long. It took three-quarters 
of an hour for the plaster to pass through the three cylinders. The 
imperfectly calcined plaster was finally sold to a New York guano works 
for $1.10 a barrel. 

After this somewhat discouraging experience, Mr. Godfrey visited. the 
New York mills, but found the owners very non-communicative about 
methods of calcining, but a foreman was found who was persuaded to 
permit Mr. Godfrey to look at the kettles in use at that place. He was 
able to keep in mind the plan of the kettles, and on his return home 
had the cylinders removed and built a couple of two flue kettles, and 
in this way introduced this method into Michigan in 1871. These kettles 
were made in Grand Rapids, and Mr. Lucas came later from New York, to 
teach the men how to calcine by this new method. This Mr. Lucas then 


departed for California and started the gypsum industry in that state 
at San Francisco. The early kettles had the bottom set in a cast iron 
ring and cemented with salt ashes and vinegar cement. At first the 
ring and bottom were cast in one piece and the shell was necessarily 
removed in order to repair any break in the bottom. Godfrey then 
tried a half-inch steel bottom, made in sections, riveted together, but 
this only lasted about two weeks. Section bottoms are held in favor 
to-day in some places, and this was probably the first attempt in this 
direction. The bottom was placed four feet above the grate, but at the 
present time the distance has been increased to seven feet. 

The cracker used at this mill has been followed in plan from that 
time in all the mills of the State and further west. It was modeled 
after the old corn cob cracker. In addition to this manufacture of 
calcined plaster, a more important branch of the work was the manu- 
facture of land plaster. The sales amounted to nearly $500 a day 
in this line alone, for a considerable period of time. 

In 1865 the Godfreys formed a partnership with Amos Rathbone 
and Geo. H. White, and bought the property of Sarell Wood & Co. for 
$33,000, changing the name of the old mill company to that of Geo. 
H. White & Co., and kept the other mill, near the mouth of the creek, 
under the name of The Florence Mills, owned by F. Godfrey & Co. The 
two firms were apparently in competition with each other. 

Mr. Geo. H. White was a lumber merchant and manufacturer, who 
was born in Dresden, N. Y., Sept. 9th, 1822, and came to Grand Rapids 
in 1842. He worked in the store of Amos Rathbone, and in 1865 entered 
the plaster business. He died September 10th, 1888. 

In 1860, Mr. James Rumsey, who had been connected with the man- 
agement of the old mill, retired from the business and was running a 
saw mill on a little branch of Plaster creek. His location was one 
convenient for farmers coming from the south over the Plankville 
road and from the southwest over the Grandville road. This situation 
led the plaster company, in 1863, to enter into a contract with him to 
add plaster grinding machinery to his saw mill and to grind land plaster 
at a fixed price per ton and which was to be sold at $5.00 a ton. This - 
contract, renewed by the new company, was in force to June 30th, 1873, 
and over 5,000 tons were sold in this way. 

By 1873 the railroads had entered Grand Rapids and the wagon traffic 
in gypsum over dirt roads had become of little importance. Godfrey 
and Brother had built docks on Grand river near their works, and large 
amounts of plaster were shipped by water. The cost of making land 
plaster in 1865 was 96 cents per ton, of which half represented the cost 
of quarrying, and half the cost at the mill. In 1873 the cost was $1.25 
a ton, and the cost of calcined plaster was $1.46 to $1.80 a ton. The 


following table will give an idea of the growth of the land plaster in- 
dustry at Grand Rapids: 

From 1842 to 1850 500 tons a year. 

From 1850 to 1860 2,000 tons a year. 

From 1860 to 1864 3,000 tons a year. 

From 1864 to 1868 8,000 tons a year. 

In 1869 12,000 tons a year. 

In 1870 12,000 tons a year. 

In 1875 the Michigan and Ohio Plaster Association was formed, with 
Mr. Bullard as President, and later with Mr. Godfrey in that office. 
The combination included Godfrey and Brother, Geo. H. White & Co., 
Grand Rapids Plaster Co., Taylor and McReynolds, Grandville Plaster 
Co., Grand River Plaster Co., Smith, Bullard & Co., Marsh & Co. of 
Sandusky, Ringland, Vincent & Meservey of Fort Dodge, Iowa. The 
association was a selling combination only and paid the companies for 
the land plaster $2.25 a ton, and agreed to sell a certain amount for 
each company and to proportion the balance of the sales among the 
companies. The profits to be distributed among the companies in pro- 
portion to their output. The association was broken up a few years 
after, and in the 80's was reorganized and lasted to about 1898. 

All was not smooth sailing with the new company of Geo. H. White 
& Co., and, on July 29th, 1876, Mr. Godfrey went into court for a dis- 
solution of partnership and for the appointment of a receiver of the 
property, and the case of F. Godfrey & Brother vs. Geo. H. White & 
Co. lasted in its various windings for twelve years. In September, 1876, 
under the direction of the receiver, a new quarry was opened near 
the present Alabastine mill, as the old appeared to be giving out. In 
1879 the land of the company, consisting of 425 acres, was divided among 
the members of the company by the order of the court and the partner- 
ship dissolved. The old mill and the adjoining land came into the pos- 
session of the Rathbones, and the new firm of A. D. Rathbone and 
Peck Brothers was organized. The Godfreys kept their land and mill. 

Near the quarry which had been opened by the receiver, the Seeley 
Brothers built a new mill about 1883, which was operated by Mr. M. B. 
Church, who had invented the Alabastine wall finish. When Church 
left the company, the Seeleys sold the mill to the Rathbones, who still 
own and operate the two plants. 

§ 3. History of the Grand Rapids District North of the River. 

In 1843 Mr. R. E. Butterworth, a cultivated English gentleman, set- 
tled on a farm two miles southwest of Grand Rapids and discovered 
gypsum in plowing a field. Becoming interested he sought for rock in 
place and discovered it in the neighboring hillside. In 1849 he opened 


the stratum and built a small water power mill near the crossroads 
and ground the rock for land plaster. In 1853 he put down a shaft 
and carried on his manufacture until 1856, when he sold the business 
to A. Hovey & Co., including Wm. Hovey and James W. Converse 
of Boston, receiving for his interests $35,000. Mr. Butterworth then 
built the machine shops in town and manufactured various kinds of 
machinery and castings, and made a special feature of gypsum ma- 
chinery. This foundry is now operated under the name of Butter- 
worth & Lowe, and is prominent in this line of machinery. 

Wm. Hovey was born in Concord, Mass., Dec. 3rd, 1812, and followed 
the trade of a carpenter and joiner. He came to Grand Rapids in 1856 
and entered the plaster business. He was general manager and treas- 
urer of the Grand Rapids Plaster Co. to the time of his death, November 
21st, 1881. 

In 1856, Hovey & Co. built a new mill, known as the Eagle mill, and 
mined 2,000 tons of rock the first year. In 1860 they incorporated as 
the Grand Rapids Plaster Co., including Wm. Hovey, Jas. W. Converse, 
Francis K. Fisher, of Boston, and Charles H. Steward, of New York. 
The original mill contained cauldron kettles holding 8 to 15 barrels and 
stirred by a V shaped rake. The kettles were emptied into a large bin 
cooled by large fans which just cleared the men's heads. 

In 1865 two six foot kettles took the place of the old cauldrons and 
these were changed in 1874 for eight foot kettles of the Godfrey pat- 
tern, and in 1892 three ten foot kettles took their place. In 1880 the 
mill was destroyed by fire, but wajs soon rebuilt and the same kettles used. 
In 1890 the Grand Rapids Plaster Co. was reincorporated with some 
changes in ownership, and in 1901 they bought the neighboring mill 
now known as the Eagle mill No. 2. 

This Eagle mill No. 2 was built in 1869 by Taylor and McReynolds 
and known as the Emmet mills. It was later sold to a stock company 
headed by A. D. and F. L. Noble, and on the failure of this company 
became the property of Noble & Co. until 1891, when it was sold to 
the Grand Rapids Plaster Co., though run as a separate corporation 
until the consolidation of 1901. 

Two other mills were built and operated for a short time in this same 
section in the later 60's. The Windsor mill was farther west and the 
Ingram mill was just west of the Emmet mill on the ground now owned 
by the English mill company. 

The English mill was erected in 1900 by Mr. P. A. English, and in 
Feb., 1902, was incorporated with the United States Gypsum Co. 

Mr. Powers, in 1896, put down a shaft within the city on the bank of 
the river near the west end of the G. R. & I. R. R. bridge, and struck 
the 12 foot gypsum stratum about 60 feet below the bed of the river. 













The rock is hoisted through an 85 foot shaft to the floor of the mill on 
the bank above. 

§ 4. History of the Grandville District. 

The town of Grandville is located six miles southwest of Grand 
Rapids on the Grand river, and at the present time has only one mill 
in operation. The old proverb that "it is an ill wind that blows nobody 
good*' appears to have found one of its applications in this section, for 
in the 60's a high wind overturned an old tree, revealing in its roots 
some small blocks of gypsum, and the ledge was soon exposed. In 
1872, Wm. Cahoon & Co., of Detroit, organized the Union Plaster Co. 
and built a mill south of Grandville, afterward known from its color as 
the Red mill. In 1873 Nearpass & Co. built a mill across the road which 
was painted white and became known as the White mill. In 1874, by 
foreclosure of a mortgage on the properties, the mills and quarries 
passed into the possession of the Union Mutual Life Insurance Co., 
and in 1878 this company operated the mills through Mr. T. N. Bros- 
man as agent. In 1880 Brosman and McKee bought the property and 
incorporated in 1881 as the Union Mills Plaster Co. with a capital of 
$150,000. The Red mill was equipped with three runs of 42 inch French 
buhrs and with nipper and cracker, with a capacity of 120 tons a day, 
a 150 H. P. engine, and three boilers. There were three eight foot 
kettles and the conveyors, elevators, etc., for the proper handling of the 
product. The plaster was cooled in large pans under which water was 
pumped by a force pump in the engine room, and the warm water was 
carried back to the boilers. The old quarry of the Red mill had been 
abandoned before this time on account of the expense of running two 
quarries, and the rock for both mills was obtained from the White mill 
quarry, where the 12 foot ledge is covered by about 8 to 10 feet of 
gravel and soil. The rock was stored in five long sheds and was sorted 
for the land plaster and for the calcined plaster. The side tracks of 
the Chicago and Western Michigan railroad were built in close to the 
mills affording excellent shipping facilities. 

During 1881 they produced 6,077 tons of land plaster and nearly 
6,000 tons of calcined piaster. A few years later the property was sold 
to Frank Noble and was again sold about 1896 to Mr. Dummer of 
Chicago, who still owns the property, though the Red mill has been 
dismantled and abandoned, and the White mill has not been running 
for the past four years. 

A short distance north of the White mill quarry is the quarry of the 
Durr mill. This mill, located three-quarters of a mile to the west, was 
the Weston flour mill, to which an addition was built for the manu- 
facture of plaster in 1875, and it became the property of Lafayette 
Taylor and Loren Day, who operated it under the name of the Wyoming 


Plaster Mills Co. Soon after this time it was bought by Mr. Day and 
then sold to Mr. Durr in 1886-7. The mill has been burned three times, 
the last fire being in 1893. The mill and quarry were sold in 1902 to the 
United States Gypsum Co., the present owners. 

In 1875 Mr. M. B. Church secured his patent for Alabastine wall 
finish, and a company was organized in 1879 and built a mill near the 
Wyoming mill. The plaster was secured from the Union Mills Co., and 
the preparation of the mixtures made in the Alabastine mill. In 1883 
Mr. Church and the Seeley Brothers built a new mill near Grand Rapids 
on tl*e present location of the Alabastine mill. 

§ 5. History of the Alabaster Deposit. 

Bela Hubbard, describes 1 a geological expedition in 1837 to this region 
in company with Dr. Houghton, and in his notes mentions the discovery 
of gypsum at the mouth of the Au Gres river. 

"In the interests of the scientific object of our tour, I will here observe 
that near the Au Gres river we discovered, beneath the clear water of 
the bay, a bed of gypsum. Subsequently an outcrop of this mineral was 
fourfd on the neighboring land, and has long been quarried with profit/' 

The plaster beds near Alabaster were first discovered by early In- 
dian traders who noticed the outcrop in the waters of the Saginaw 
•Bay. In 1841, on the completion of the first government survey of 
this district, Mr. Wm. McDonald, an Indian trader in the employ of 
the American Fur Co., made an entry a mile in extent along the shore. 
He later sold a portion of his interest to James Fraser, Harvey Wil- 
liams and Alfred Hartshorn, who explored the beach but found nothing 
except gravel and sand. Others later sought for the gypsum in the 
sink holes of the region, for they failed to recognize the fact that these 
places owed their formation to the loss of gypsum through solution. 

In the later 50's Wm. S. Patrick carried the mail through this sec 
tion from Alpena to Bay City by dog train. An old squatter, who had 
taken possession of some land near the present Alabaster quarry, one 
day showed a piece of the gypsum rock to Patrick, who took it to Bay 
City and showed it to Mr. Geo. B. Smith. Mr. Smith's father, B. F. 
Smith, owned a quarry near Sandusky and a gypsum mill in the city 
of Detroit. Patrick, on his return, bought the land, paying for it two 
dogs and $ 10, and he in turn sold it to Mr. Smith, who opened the first 
quarry in 1862. On the death of Mr. Smith, Mr. A. F. Bullard, B. F. 
Bullard, and the estate of G. B. Smith formed the company of Smith, 
Bullard & Co, and in 1876 the name was changed to Smith and Billiard, 
who sold to B. F. Smith, who in turn sold a part interest to W. A. 

l A Michigan Geological Expedition, a paper read before the Historical Society of Detroit and pub- 
lished in Michigan Pioneer and Historical Collections. Vol. HI. p. 199. Memorials of a Half Century, 
p. 86 


Avery and T. G. McCausland, operating under the name of B. P. Smith 
& Co. This company was reorganized in 1891 as the Western Plaster 
Works and changed to the Alabaster Co. in 1898. It is now known as 
the Alabaster plant of the United States Gypsum. Co. In 1891 tire de- 
stroyed all the property and the mill was rebuilt in 1892, and another 
mill was built at South Chicago to supply the World's Fair trade. 

In the early days of the Alabaster quarry development, small mills 
for the manufacture of land plaster at Winona, West Bay City, and 
Monroe were supplied with the Alabaster rock. 

The first apparatus used for calcining was a system of revolving 
cylinders which proved unsatisfactory, and these were soon replaced by 
kettles. The fuel used for the purpose of calcining was wood until 1898, 
when the railroad switch was built and coal replaced the wood. 

In 1870 Mr. Chas. Whittemore, a lumberman of Tawas City, opened 
a second gypsum quarry about three miles south of the Alabaster quarry 
near the water of the bay, and made land plaster for the farmers of that 
region, but on account of trouble with water abandoned the work a year 
or so afterward. 

At the present time the Alabaster Co. has established a hotel, post- 
office, and some 40 dwelling houses for the workmen, forming a very 
comfortable town located six miles from Tawas City and 42 miles 
from the mouth of Saginaw' river, fronting the Saginaw Bay. They own 
about 200 acres of land and have built a two story warehouse and 600 foot 
pier for loading the sailing vessels, and the town is connected by switch 
with the Detroit and Mackinac railroad, which connects with the Pere 
Marquette at Bay City. 




§ 1. Geological Section. 

The geological formations of the Lower Peninsula of Michigan are 
represented by an interior Coal Measure basin (Fig. 8), surrounded by 

Fig. 8. Cross section of the Lower Michigan Basin. Horizontal scale, 1 mile =.185 inch; 
vertical scale, 1,200 feet =.321 inch. 

From U. S. GeoL Survey Water Supply Paper No. 90. 

more or less complete and irregular concentric circles of the older 
formations down to the Lower Helderberg, or Monroe dolomite, the upper- 
most stratum of the Silurian. 

The division which is of special importance in the study of the 
gypsum deposits is the Sub-Carboniferous of the older geologists. The 
lower portion of this formation had been named before 1S70 the Waverly 
by the Ohio geologists, and in Michigan had been called by Winchell 
the Marshall. In this same year he proposed the name Mississippian 
for all the rocks from the Burlington limestone up to the Chester lime- 
stone in the Mississippi valley. 

In 1891 Prof. II. S. Williams proposed to substitute for Sub-Carbon- 
iferous, the name Mississippian series "to include all the formations con- 


taining Carboniferous faunas from the top of the Devonian to the base 
of the Coal Measures." He further divided the series into three epochs; 
from below upward, Chouteau, Osage, and Ste. Genevieve. Keyes later 
divided the series into four epochs, the Kinderhook = Chouteau, the 
Augusta = Osage, the St. Louis and Kaskaskia = Ste. Genevieve. 

The Chouteau was named from the Chouteau limestone of the Mis- 
sissippi valley. This stone was later found to be equivalent in age to 
the Kinderhook of Illinois, a name given earlier and so entitled to hold 
by the law of priority. The Osage formation included the Burlington 
and Keokuk limestones. Keyes proposed the name Augusta for the 
group, because of the typical development of the. formations near the 
town of Augusta in southeastern Iowa, and also because the rocks desig- 
nated as Osage were later shown to be Burlington in age. 

Above the Augusta or Osage is found the St. Louis limestone, over- 
lain in part of the area by the Chester shales. These shales were first 
named in print in 1865, but Hall had given the name Kaskaskia to the 
same group in 1856. Some writers have united these two groups under 
the name of St. Louis-Chester, or Kaskaskia, but according to Keyes, 
the Kaskaskia and St. Louis "were separated more widely than any 
other two members of the entire Carboniferous of the continental in- 
terior, faunally and especially stratigraphically." 

The Waverly group of rocks in Ohio appears to be equivalent in part 
to the Marshall of Michigan, the Kinderhook of Illinois, and to the Chou- 
teau of the Mississippi valley. This correlation was made many years 
ago, and through error was regarded as equivalent to the Chemung 
division of the Devonian of New York. 

In Michigan, Winchell. 1 in 1862, described a series of sandstones, 296 
feet in thickness, whose upper portion was more firmly cemented and 
more homogeneous than the lower, and further contained fewer fossil 
remains, in fact was almost without organic remains. The upper part 
was called the Napoleon Group, or the Upper Marshall, and the lower 
portion was called the Marshall Group, equivalent to the Waverly in 

Above this series, in the vicinity of Grand Rapids, is a group of shales, 
limestone, and gypsum layers, called by Winchell the Michigan Salt 
Group. This formation has been shown by Rominger and Lane to be 
destitute of salt beds, and the Saginaw valley and principal Michigan 
brines come from below this horizon, so that it seems advisable to follow 
Lane 2 and call it merely the Michigan Group. 

Above the Michigan Group comes the Carboniferous limestone of 
Winchell, exposed at Grand Rapids and other places around the border 
of the coal measure basin. It is equivalent to the Bayport limestone 

lAmer. Jour, of Science, Vol 33, pp. 352 766; 1882. Bull. U. S. Geol. Survey, No. 80, p. 177, by 
*Mich.Geol. Survey, Vol. VII, Part II. p. 13. 

54 * GYPSUM. 

of eastern Michigan, to the Maxville limestone of Perry and Muskingum 
counties in Ohio, and to the upper part of the St. Louis limestone of 
the Mississippi valley. Over the Carboniferous limestone, the Saginaw 
Coal Measures are found forming the interior basin. The Waverly 
group of Michigan, including the rocks described up to the Carbon- 
iferous limestone, according to Rominger, 1 "forins underneath the drift, 
the surface rock over half the extent of the Peninsula, but its natural 
outcrops are very limited, either horizontally or vertically." 

The Mississippian series in Michigan forms a basin shaped fold, and 
in the center of the Peninsula it is overlain by the Coal Measures, and 
can only be mapped in such sections by the aid of well records. 

The whole series of Michigan presents more or less irregularity, in 
places represented by shales, and again by sandstone apparently con- 
temporaneous. The Michigan group in places is cut out entirely on 
the border of the Coal Measures, and again the Bayport limestone is 
present and the lower gypsum beds are gone. This limestone at Grand 
Rapids is about 50 feet thick and rests on the gypsum formation. 

In the interpretation of the geological history revealed by these rocks 
and their relations, the writer wishes to acknowledge his indebtedness 
to the various papers of Weller, Lane, and Keyes. 

§ 2. Geological History of the Michigan Basin. 

At the opening of the Carboniferous period, Lower Michigan, Ohio, 
and a large part of Pennsylvania, were covered by a gulf which opened 
to the northwest across Illinois and Minnesota. In the earlier part 
of the Mississippian epoch, the land was sinking around this gulf, 
especially to the south and southwest, and in this sinking area were 
deposited the sediments of the Kinderhook stage, forming limestones, 
sandstones, and shales, mainly shallow water deposits irregular in ex- 
tent, varying in fossil contents, so that the same series of rocks has 
been given a variety of names by geologists. These names are often 
used in local geology, but now are known to be contemporaneous, and 
they are included under the name of Kinderhook. 

By the close of this division of time, the large gulf extended south into 
Arkansas and Tennessee and west to the Rocky Mountains, and opened 
northwest across the Dakotas. 

For a long period of time the salt water gulf remained stable and 
quiet supporting a rich fauna of corals and crinoids which have formed 
the Burlington and Keokuk limestones known throughout the world on 
account of the variety and perfection of their crinoid and brachiopod 
fossils. These limestones and other formations, related in time, have 
now been grouped under the name of Osage or Augusta. 

iMich.Ueol. Survey. Vol. Ill, Part I. p. 69. 



The following sketch (Fig. 9) by Lane, 1 modified from Keyes' section, 
will show the relations of the rocks of the Mississippi valley to those 
of Michigan. 

While there were many local and minor 
variations in the physical conditions^ and 
therefore in the life characters in this 
gulf, there was a greater and more import- 
ant contrast in these characters between 
the eastern and western portions, sepa- 
rated by the Cincinnati island. These have 
been named by Weller' the eastern or 
Waverly province, and the western or 
Osage province. 

In the Kinderhook gulf, the faunas were 
intermingled to a very considerable ex- 
tent; but in the Osage age, the clear 
waters of the Osage gulf supported a 
fauna which could not flourish in the sedi- 
ment laden waters of the Waverly prov- 

The land to the northeast of this Car- 
boniferous gulf was above sea level, the 
drainage system of that highland carried 
a large quantity of mud and sand sedi- 
ment into the Waverly gulf, forming the 
conglomerates, sandstones, and shales of 
that area. The Cincinnati island afforded 
a partial barrier to the drifting of the 
sediment into the clearer Osage waters 

At the close of the calm Osage age came 
a series of uplifts and depressions, whose 
effects are seen in the Mississippi valley 
and at the east. The St. Louis limestone 
was formed in waters extending 200 miles 
further north than those of the Osage, and 
this northward extension was followed by 
a retreat of 400 miles to the south. 

In the eastern part of the Waverly gulf, the changes began earlier 



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lMlch. Geol. Survey. Vol. VII, Part II. p. 15. and Vol. VIII, Fig. i. 
•Journal of Geology. Vol. VI, p 306. 


than in the Osage gulf, and the coast line, according to Lane, 1 receded 
westward from western New York and central Pennsylvania, until a 
large part of Ohio and Indiana were out of water by the end of the 
Marshall or Waverly age. This left the Michigan basin enclosed be- 
tween the mass of land at the northeast, and probably also at the north- 
west, and the low land over northern Ohio and southern Michigan. 2 

On the south side of this low land were deposited the sediments form- 
ing the coarse sandstones and conglomerates of the Logan group laid 
down irregularly in Ohio with an average thickness of 200 feet. To the 
north side were deposited the sediments forming the rocks of the Michi- 
gan group, shales, limestones, and beds of gypsum. 

The Mississippi extension of the St. Louis is represented in Michi- 
gan by the Bayport limestone, in Ohio by the Maxville, which comes 
above the Michigan Group. This group would correspond in time with 
the Burlington and Keokuk, or the Osage (Augusta) of the Mississippi 
valley. The thickness of the group in Michigan is 232 feet (Lane, Vol. 
VII, Part II, p. 16). the Augusta in Iowa is 230 feet, the Logan in Ohio 
200 feet. 

§ 3. Michigan Group. 

The Carboniferous, Bayport, or St. Louis, limestone in Michigan is 
also called by Lane the Upper Grand Rapids series, and the Michigap 
group is known as the Lower Grand Rapids. 

At Grand Rapids, the typical locality for the section, the lower series 
outcrops to the south of the city as a group of shales, thin bedded 
limestones, and gypsum layers; while the upper series outcrops along 
the river in the city nearly to its north limits.' A number of quarries 
have been opened in the bed of the river, and, according to Rominger, 
the contact could be seen at the foot of the Rapids in the earlier his- 
tory of the city. This limestone is about 50 feet thick, and the continua- 
tion of the section downward is given in the chapter on well records. 

The only localities in Michigan where gypsum is found in this forma- 
tion near the surface, are in the vicinity of Grand Rapids and at the 
east near Alabaster. The formation, however, is found in a belt of 
varying width bordering the coal basin, and throughout the most of the 
area it is more or less concealed by the overlying drift. 

§ 4. Glacial Geology of the Grand Rapids Area. 

Mr. Frank Leverett has made careful studies on the glacial geology 
of the area around Grand Rapids, and a condensed account of this 
geology was prepared by Mr. Leverett and published in a report on the 
Grand Rapids flora, by Miss Emma Cole.* Mr. Leverett has kindly sent 
me a copy of this part of the report, which is as follows: 

iMichigan Geological Survey, VoL VII. Part II. p. 15. 

«The extension of the Cincinnati Island above mentioned. 

»See Whiitemore Proc. Mich. Acad, of Sciences. Also Strong. Proc. Kent ScL Inst. No. 3. 

<See also paper by B. £. Livingston, In Ann. Report for 1901. 





















"The features are somewhat intricate, but they fall in naturally with 
the view that there was a conjunction of two lobes in this vicinity. When 
the ice extended nearly to the southern border of Michigan, the junction 
between the Saginaw and Lake Michigan lobes was in a great belt 
of gravel that is traversed by the Grand Rapids & Indiana R. R. south 
from Kalamazoo, and the point of the reentrant angle was in the great 
ridges southeast of Gun Lake. 

"From this position the ice melted back until the point of the re- 
entrant angle between the ice lobes was at the Dias Hills, a few miles 
south of Grand Rapids, and there a halt of some length occurred. The 
gravel tract between Dias Hills and Gun Lake was formed at that time. 

"The ice then melted back sufficiently to bring the reentrant angle 
up to the bend of Grand River at Plainfield, and again halted. At that 
time the Lake Michigan lobe formed the ridges and hills that lie on the 
west side of the Grand River from Rockford to Jenison, and its margin 
continued southward past Jamestown. The Ss^ginaw lobe at the same 
time covered the region immediately east of Grand Rapids, its margin 
being in the eastern edge of the city; and it built up the rolling coun- 
try around Reed's Lake, and its continuation in the districts to the 
north and south. Meantime the water found its escape southward over 
the site of Grand Rapids, and on through the gravelly lowlands that 
lead past Carlisle to the Black Ash Swamp, and thence to the pine 
plains of western Allegan County, where it entered Lake Chicago, a 
lake that then filled the south end of the Lake Michigan Basin and 
discharged southwest past Chicago to the Illinois and Mississippi rivers. 

"In melting back from this position, the ice next made a stand near 
Cedar Springs, and built up the prominent ridges northeast of that 
village. From these ridges the margin of the Saginaw r lobe passed east 
of south near Nagle Lake to Grand River below Low r ell, and thence on 
past Alto, while the margin of the Lake Michigan lobe passed south- 
west near Sparta and Englishville and formed the western part of the 
great belt of rolling land west of Grand Rapids. 

"At length, after several halts that need not be enumerated here, the 
Saginaw lobe had melted so far back that its front was on the slope 
towards Saginaw Bay. A lake then formed in front of it, known as 
Lake Saginaw, which discharged down Maple river to Grand River at 
Lyons, and thence on past Grand Rapids into Lake Chicago. The chan- 
nel divided near Jenison, one branch turning down the present river 
to enter Lake Chicago near Lamont, while the other led southwest past 
Hudsonville to enter the lake at Zeeland. Great gravelly deltas were 
formed by each branch of the old outlet at the places where they entered 
the lake. Much of Allendale Township, Ottawa County, is in the delta 
of the north branch, while Zeeland stands on the delta of the south 
branch. As these gravelly deposits are now 00 to 70 feet above Lake 


Michigan, it is certain that the level of Lake Chicago was about that 
height above the present lake. Later it dropped to lower levels, and 
the outlet of Lake Saginaw along Grand River valley become corre- 
spondingly deepened. 

"The variations in the drift material gave rise to several classes of 
soil ranging from heavy clay through loamy clay, clayey loam, sand 
and gravel, up to coarse cobble. It is usual, however, to find in gravelly 
places a sufficient amount of fine earthy material to afford a suitable 
matrix for plant roots. 

"Perhaps the coarsest deposit within the Grand Rapids district is 
that in the old lake outlet. Between the city and Grandville the cur- 
rent of water removed the fine material to such a degree that the soil 
is very stony. In the western part of Grand Rapids and for some miles 
above the city large numbers of boulders were present in this outlet 
before the residents made use of them in building. The soil among the 
boulders was, however, not too coarse for plants to thrive. This same 
lake outlet carries also some of the most extensive swampy tracts in 
the district; the Zeeland swamp southwest of Hudsonville, the Cedar 
swamp west of Jenison, and *the Burton Avenue swamp southwest of 
south Grand Rapids, being illustrations. But this swampy condi- 
tion is due to subsequent plant growth in the part of the channel hav- 
ing exceptionally flat bottoms, rather than to any deposit made by the 
outlet. It is found that sand and gravel deposited by the lake outlet 
underlie all the swamps at a depth of only a few feet. 

"The strip of gravelly sand which extends from the bend of Grand 
River near *Plainfield southward along the east side of Grand River 
through Grand Rapids and to Carlisle, being in the line of a stream 
of water, carries but a small amount of clayey or fine material, and is 
less productive than the heavier 'soils on the borders of this old stream 
course. In the immediate vicinity of Grand Rapids it has the further 
disadvantage of being situated on the border of a deep valley into 
which the waters drain rapidly after a rain. The lightness of the soil 
is shown in the character of the vegetation, it being a strip of 'oak 
openings.' In this old stream course, the extensive Black Ash Swamp 
has been developed; but, as in the lake outlet, this is due to subsequent 
plant growth, and sand may be found by probing to the depth of a few 

"The grade of soil next finer than the gravelly sand of the old stream 
courses is the sand found on the bluffs of the Grand and Thornapple 
rivers above the bend at Plainfield and on the border of several tribu- 
taries of Grand River, both above and below Grand Rapids. These 
sandy deposits have apparently in some cases been drifted beyond the 
limits of the streams that contributed them, being very irregular and 


"The greater part of the Grand Rapids district lies on the uplands 
that were feebly or imperfectly acted upon by currents of water during 
the melting of the ice sheet. 

"As a consequence, the soils contain a large amount of fine material 
together with the coarse stones of the drift. The proportion of fine 
material determines whether it is a heavy clay, a porous clay, or a loamy 
soil, and this proportion often varies greatly within the limits of a 
small field. In these uplands there are numerous basins formed by 
the irregular heaping of the drift, aided perhaps by the unequal settling 
of the drift material. These, because of imperfect drainage, usually con- 
tain either lakes or swamps. The basins are especially numerous in 
Grand Rapids Township, from Reed's Lake northward, but are not rare 
in any part of the uplands of this district." 

§ 5. Topography of the Grand Rapids Area. 1 

The Grand Rapids area in Kent county is drained by the Grand 
river which rises in the southern part of the State in Jackson Co., 
and flows northwest past Lansing, turning west near Ionia, making 
a horseshoe bend to the north near Grand Rapids and, flowing south 
through that city, turns southeast to ( i rand vi lie, where it takes its 
northwest course again, emptying into Lake Michigan at Grand Haven. 
Its length is over 275 miles, including windings. 

The Grand river flows from the north through Grand Rapids in a 
series of rapids which terminate below the center of the city near the 
Fulton street bridge. The river falls less than one-half foot in a distance 
of one mile from north of the city limits to Coldbrook street and in 
the next mile the fall is 12 feet, and from the lower part of the city to 
Lake Michigan, a distance of 50 miles, the fall is only 5.8 feet. 

The river flows in a very straight channel, 000 to 900 feet in width 
cut in the valley, which is one mile to one and one-fourth miles wide. 
The banks on either side of the valley form bluffs 150 feet in height. 
Near the city the river is close to the east bluffs, but towards Grand- 
ville the valley broadens to the south. 

The bluffs are gravel ridges cut by erosion into elongated or rounded 
hills. One of these extends through the city, east of the river, from 
Coldbrook avenue near the north end of the city, to Fulton street, a 
distance of one and one-fourth miles. A second ridge, really a continua- 
tion of the first one, extends from south of Fulton street to the south 
end of the city. The ridges are composed of gravel and boulders of 
varying size, with occasional boulders of limestone and gypsum. The 
river plain is composed of sand and silt. 

To the south of the city the drainage is carried into the river by 
Plaster Creek, which rises in the southern part of Kent county and flows 

iS£c map published in Anmal Report for 1901. 


north for eight miles and then northwest for about ten miles. Near 
Grandville the area to the south is drained by Buck Creek, which 
rises in the vicinity of the head waters of Plaster Creek and flows 
northwest ten miles. These two streams are small, but they formerly 
furnished water power for the gypsum and flour mills near their mouths. 
The towns in the gypsum area are Grand Rapids, a city of 100,000 
people, with its numerous mills and furniture factories; and Grand- 
ville, a town of a few hundred people. The area is traversed by the 
Pere Marquette R. R., which passes through Grand Rapids and through 
Grandville to Holland and Chicago. The Grand Rapids mills are also 
reached by the Grand Rapids and Indiana, and the Lake Shore and 
Michigan Southern railroads. The Detroit & Milwaukee branch of the 
Grand Trunk system also crosses the area. 

§ 6. The Alabaster Area, by XV. M. Gregory. 

1. The Size of Area. 

The area under consideration (Plate IV) is located on Saginaw Ray 
on the northeastern side of the Lower Peninsula of Michigan, com- 
prising parts of the counties of Arenac, Ogemaw, and Iosco. The size 
of the area is some 40 by 30 miles, and comprises some 600 square miles. 
The geological formations here exposed extend from the Coal Measures to 
the Coldwater shales. The former State geologists Rominger and Winchell 
accomplished the most work, which w r as confined principally to the 
outcrops along the Lake Huron shore. Some of the outcrops of the 
interior which have not been described before will here be treated. 

2. General Topography. Highest ami Loicest Land. 

The highest land of this area is in the northwest, the contour map 
showing a general slope from the northwest to the bay. The greatest 
elevation (850 A. T.) is at Turner's Corners, southwest of Maple Ridge, 
and other points which have considerable elevation, are Maple Ridge, 
which is on the crest of the Saginaw r moraine and has an elevation of 
£03 A. T., and Pinnacle Hill, which is the highest point south of the 
Rifle river, and has an elevation of 765 A. T. 

The lowlands are found bordering the lake shore and extending up 
the river valleys. Some of these lands include large marshy "prairies," 
such as are found at the mouth of Rifle river and along the lake shore 
near Pine river and Saganing. 

3. Glacial Geology. 

The surface forms of the region are due to glacial action, in fact the 
predominating character of the surface topography outside of the lake 
formations was determined by the great ice sheets, which recently, in a 
geological sense, covered this country. These forces were not always de- 
structive, but frequently constructive. The old rock surfaces which 


existed before the time of the ice cap have been smoothed off and the old 
valleys filled with glacial till. Distinct traces of some of these old valleys 
are found some four miles west of Alabaster, running north and south. 
Here wells are often drilled through the drift some 150 feet before 
reaching the rock. 

Where the end of the ice sheet stood for a long time large mounds 
of assorted till were made on top of the rock. These mounds were 
continuous along the ends of the glacier and now stand up as high 
ridges or moraines. The crests of some of these moraines are seen in the 
region of Sterling, Prescott, and Taft. The drift is nowhere over 150 
feet in thickness, its average depth is from 25 to 40 feet. 

The moraines which are now present are moraines of retreat, the 
earlier ones being scrubbed out by advance of ice ; the height of these 
moraines is never over 100 feet above the general surface of the country 
and some of them may be traced continuously across the country. One of 
the most prominent of the moraines of this region starts in the south- 
west near Moore's Junction and parses across to Sterling, Summit, Pres- 
cott, and Taft, and has been called by Taylor, the Port Huron-Saginaw 
moraine. This is the highest moraine on the map, Plate IV, and marks 
the position of the Huron ice lobe during one of the periods of retreating 

The one which starts at Harrisville and Alcona is traced southward 
to a point north of Tawas Lake down to the Vines P. O. and, curving 
slightly to the southeast, to a large spur midway between Tawas City 
and Alabaster, where it drops off sharply, may be traced as a water 
laid moraine from this place to Au Gres, where it passes into Lake 
Huron. The Alcona moraine in the region of Alcona is very marked 
in itsmorainic character, being very rolling and irregular in outline; 
as it is traced to the south it becomes more subdued, exhibiting its 
water laid character. The bedding at Seven Mile Hill on the Au Sable 
and Northwestern II. K. shows clearly that the ice once stood at the 
eastern edge and that the drainage was to the west, forming the Au 
Sable overwash plains which are traced as far south as Moore's Junc- 
tion, always being found as sand beds just west of this clay ridge. 
This moraine is believed to exhibit one of the characters which is pecu- 
liar to moraines passing from surface forms to water laid forms. 
It was formed after the Saginaw-Port Huron moraine and a string of 
lakes exist between the halt of the two moraines. 

The interesting feature which always accompanies the moraines in 
this region is the overwash plains, or as 'they are mow popularly called 
the sand plains. These are very familiar to the residents of the district 
as being regions which absorb water very rapidly and contain no soil 
which is adapted to cultivation, and grow a familiar plant society char- 
acterized by jack pine, sweet fern, and scrub oak. As has been before 

62 GYP SUM. 

stated, these plains were formed when the ice stood on the different 
moraines and are the products of drainage along the western edge of the 
ice. In some places, such as Iosco county, north of Tawas City, there 
is quite a deep trench between the place where the ice stood and the 
plain; this is believed to be an excellent example of ''fosse." The sand 
plains in the region of Pinnacle Hill were formed as a delta in some 
stage of the glacial Lake Warren, those in the region of Alger being 
formed in an earlier stage of the lake called Saginaw by Taylor. These 
sand plains comprise all the northwestern parts of Iosco county and 
almost wholly the entire northwestern section of Arenac county. 

The conditions which were present during the retreat of the glaciers 
were such that at the south and west was higher land, and the ice 
as it stood on the moraines often extended across to higher land in 
the south, so that in front of the lobes was a lower region than that of the 
surrounding surface, which filled with water from the melting and retreat- 
ing glacier, and thus glacial lakes were formed. The beds and beaches 
of these old lakes form a very conspicuous feature of the topography 
of this area. That these lakes persisted for a long time is clearly cer- 
tain from the extent of their beach lines and their development and 
many lake histories have been recorded and perserved by these fossil 
beaches. The highest beach of this region is that of old Lake Saginaw. 
It was into this lake that the early drainage of the Au Sable 
river was directed by the western edge of the ice. The next lake 
which left two distinct beaches was Lake Warren. The first beach 
was the Upper Forest, 1 usually formed at 775 A. T. This beach is very 
distinctly shown in the region of Sterling, and is found again as a 
beach of water worn gravels east of Maple Ridge, is present north 
and east of W T hittemore, and is believed to lw bordering on Bissonette, 
Tp. 24 N., R. 7 E., Sec. 11. The lower one is well developed, and marks 
a slight fall in the level of Lake Warren, and is traced from Sterling 
across to Emery Junction and the edge of the sand plains northward 
to Seven Mile Hill. It is believed that while the lake stood at this 
level and at the place preceding, that the delta which comprises the 
region of Pinnacle Hill in Arenac county, was formed. The Grass- 
mere 1 beach is not distinct in the northwest but seems to appear in 
the vicinity of Deep river on the Michigan Central R. R., having an 
elevation of 655 feet A. T. It is made out rather indistinctly at the 
edge of the old or Pinnacle Hill delta, and it appears again west 
of Turner, in a well marked ridge, and it is traced to the northeast to 
a point south of Emery Junction, where it extends directly east on 
top of the well marked lobe of the Alcona moraine, and nearly reaches 
Lake nuron, having an elevation of 650 A. T. Thence turning north, 

lThe correlation of these beaches Is with the Huron county report, Vol. VIII. At the date of 
publication Messrs Leverett and Taylor are engaged in revising this, and changes may be Involved 
in the names. L. 


going west of Tawas City and also of Tawas Lake, it is believed to 
pass along the foot of Seven Mile Hill. The Algonquin Beach is the 
best marked of all these beaches and has been traced almost con- 
tinuously across this region. It is first found in the southeastern part 
of Arenac county, west of the I). & M. B. B., having an elevation of 
605 A. T., and being well developed in this region. This is traced easily 
to Pine river in a series of beaches, which are some 15 to 20 feet above 
the level of Lake Huron and have in front of them smooth till plains. 
This is something exceptional in the way of beach structure and may 
be explained on the supposition of the formation of these beach ridges 
by means of push ice in old Lake Algonquin. On going north the beach 
becomes indistinct in the region of Au Ores swamp, but is found ap- 
pearing again clearly at Alabaster, with an elevation of 005 feet A. T. 
It is traced along the front of the Alcona moraine a way, and then dis- 
appears, being cut away, until it reaches Tawas City, where the beach 
is found and a well developed bar which formed in front of the 
beach and eventually became the beach by the cutting off of the water in 
the rear. This little episode in the history of the Algonquin beach 
and the formation of the lake back of Tawas City and the subsequent 
drainage of this lake is very clearly shown in the region called the 
"glen." The next beach below the Algonquin is the Xipissing and is 
in places, in the southern part of Arenac county, not over 10 feet above 
the level of Lake Huron. Its chief features are destroyed in main- 
places by erosion, or wind action accentuates its normal development. 
In the upper part of Iosco county the beach is 15 to 20 feet above lake 
level and is, if exposed to the wind, sure to be changed into ridges 
w T hich are slowly traveling the shore. Such dunes are shown at the 
old Hale mill and also at the Tawas Beach Park resort. Some of these 
dunes show what might be termed wind ripple action, being blown into 
little ridges, which are exactly similar to ripple marks formed in shal- 
low water. A few of these dunes travel quite rapidly, and in some* 
of these places trees have been known to survive passage of sand 
over them. 

-}. Additional Relief Forms. 

Most of the forms which are a conspicuous part of the topography 
are due entirely to glacial action, and as erosion has had but a small 
opportunity to work over these forms, the prevailing relief is one of 
youth — maturity in laud form development 1km ng reached only along the 
river bottoms and lake shores, but erosive action has been enough in 
some places to accomplish a considerable cutting away of the old lak«» 
beaches. The inland lakes are as yet but little tilled and the swamps are 
largely the result of the immaturity of the* drainage system. The Au 
Gres swamp is an excellent type of this development. 


One of the features of the old rock topography, the only remnant 
of this form which has an influence on the present surface features, 
is the limestone ridge which extends from Point Au Gres west to Duck 
Lake, from thence north and west to the Griffin quarry and the Tyler 
outcrop, becoming lost underneath the drift of the northwest. This ridge 
stands up because of the hardness and the lithological character of its 
composing members, which are a hard dolomitic limestone and hard cal- 
careous sandstone. 

5. Recent Shore Forms. ' 

Between the lake level and the Nippissing beach is a strip of land which 
is due entirely to recent lake formations and some of these are within 
recent historic times. The general shore structures of the eastern edge of 
tliis area show the direction of the adjustment of the beach to the lake 
currents by the smooth curves convex to the present in the outline of the 
shore, both in the larger features and the smaller ones (?). The most 
interesting place where these recent formations have been more rapidly 
built, is at Tawas Point. The places in the "bight" of Tawas Bay show 
how the building at this point is gradually weakening the building effects 
of the waves on the shore. 

One of the familiar features along shore is that of sand dunes; 
in many places arranged by storm waves and wind action into lenticular 
dunes with the longer axes northeast and southwest. These are often 
cut into several smaller ones, later by wind action or perhaps the entire 
top blown off, forming a dune which resembles a crater of an old 

The Tawas river and other rivers of this section have a tendency to 
build deltas where the force of the river currents is less than that of 
the lake currents. This has taken place at the mouth of Tawas river. 
The building takes place in the summer and in the spring and fall. The 
current of the Au Sable is much stronger than the prevailing lake cur- 
rents and the sediments are carried some two miles down the shore, 
where, according to Capt. Small of the Tawas U. S. Life Saving Station, 
there is a large shallow area, some one-half mile off shore, and this is 
being converted into an island. The Rifle river has built a large delta at 
ils mouth, some five miles square in area, and the Au Ores river has a cur- 
rent which is so sluggish that a channel to the Saginaw Bay is kept open 
with difficulty, and a long area of land in front of the river mouth is 
slowly forming into the river delta. 

6. Sink Holes. 

Some of the forms which are very limited in extent, but constitute 
a peculiar fenturt* of the surface, are known as sink holes, and have 
been formed in the limestone or in the gypsum by the dissolving action 
of the water forming large circular pits, 10 to 15 feet across and 9 to 







10 feet deep. Such structures are found below Alabaster in Iosco 
county, also west of the D. & M. R. R. near the Dryer place, and at Glen- 
don dam on the east side of the river; these structures, while not an 
important topographic form, are believed to be important in the drain- 
age of the region in which they are found and are the best developed 
at Alabaster of any of the regions in which the structures occur. 

7. The Drainage. 

The drainage of this region is largely determined by the character 
of the country, as the rain fall of the sand plains passes quickly to 
the water table, which is on the underlying clay whose depths 
from the surface averages near 15 feet, while the water falling on the 
clay flats is almost all held on the clay surface until removed by the 
surface drainage. The sand plains give rise to a large number of springs 
at their edges or in the regions where they are cut by the rivers. All 
the creeks of this region which are important feeders of the larger 
rivers can be traced directly to their origin on the edge of the sand 
plains. The springs at Pinnacle Hill on Rifle River are an example of 
springs formed by a river cutting down to the under clay of the said plain, 
and there are several such springs found along the Au Sable river. Along 
the Au Gres river are many of these springs, which appear between the 
sand and the under clay. The entire drainage of the eastern half of this 
area is very irregular and discordant. The shortest and most natural 
route for the water to take to the lake, is effectively blocked by the 
Alcona moraine, and the w r ater falling quite near to the lake is carried 
away some distance to the Au Gres river, where it slowly passes through 
the Au Gres swamps and out to the lake. In the spring swampy lands 
along the Au Gres slowly fill with water, which renders useless for a 
long period during the early spring a large tract of land which would 
otherwise be excellent for cultivation. Attempts have been made to 
remedy this by clearing out the outlet of Duck Lake and by building 
drains to carry the water directly into the Au Gres river, as the drain 
east of Twining and also the "Bum" drain east of Turner. This 
condition in the region of Alabaster is possibly to be corrected by a pretty 
example of stream capture, as there are many small stream creeks 
"gnawing" back from Lake Huron into the lake side of this moraine, 
and in the spring when the water is high in the Au Gres basin, a small 
part of it comes over the divide in these creeks. One of the largest of 
these spring creeks is situated midway between Tawas City and Ala- 
baster, and has cut a deep ravine into the moraine here and in front 
has built a fine alluvial fan or "freshet" delta. 

8. Rifle River. i 
The Rifle river is a good example of the typical streams of this 

section, it having had in former glacial time an abundant supply of 


water which brought a large amount of gravel. The river had to 
aggrade its course because of increased supply of material and as 
the volume of water became deficient by the retreating of the glacier, 
the slope of the old river was not steep enough and thus the stream 
was compelled to grade its course, cutting deep into the deposits of 
sand and clay gravel. The lowest beds of the formations exposed 
in the river banks are solid lake deposited clays, which were formed 
when the lake stood at a higher level and the river had its entrance 
to the early glacial lakes farther to the north, and then as the shore 
of the lake was lowered, on top of the clay was deposited a series 
of overwash deposits, which vary from 15 to 20 feet in thickness and 
are almost wholly composed of fine white sand. It may be explained 
that the absence of a deposit of coarse gravels on top of the clay may 
mean that the lake fell rapidly, giving no time for the deposition by 
continued action of other shore deposits, than fine sand, not giving 
an opportunity for the working out of the heavy boulders and pebbles. 
The river shows, in many places, a succession of terraces cut in the 
old gravels and in places there are cusps on the spurs. Where the 
river flows across the moraines the boulders are sorted out and left 
in the river bed, forming riffles or slight rapids. 

The flood plain of this river is not well developed above Omer, but 
well enough developed so that it sweeps around the ends of some of 
the spurs and possibly may be classed as a "scroll pattern flood plain." 
Below Omer the river has many ox-bow cut-offs and a great extension of 
the flood plains. It has no branches of any size from the south and is fed 
by spring creeks from a clay country from the north and rises in the 
region of Rose City and Lupton. At the West Branch bridge, it cuts 
through an exposure of some 20 feet of Marshall sandstone; below 
this exposure some two miles there is a formation of limestone and 
sandy shale which belongs to the Maxville rocks. At a lumber dam, 
northwest of Pinnacle Hill, there is an exposure of bed rock which 
may be classed with the Michigan group. Following down some two 
miles are excellent exposures of fire clay and black shale, exposing a 
pocket of the coal series of Michigan. The outcrop at Omer is the fine 
white sandstone which is believed to be the base of the Michigan coal 
series. This formation is exposed in several other places, from this point 
down the river to the mouth. 

§ 7. The Paleozoic Geological Formations of the Alabaster Area. 

In this area are excellent exposures of the Michigan coal series, the 
Maxville limestone, Michigan series, Upper Marshall or Napoleon and 
Coldwater or Cuyahoga shales. The outcrops are rare, but all of the 
formations are represented with the exception of the Coldwater shales. 
The best outcrops are those of the Maxville limestone and the Michigan 


series. Much of the knowledge of the rocks is based upon the records 
of the salt wells which were drilled years ago to supply brine for salt 
manufacture, which was carried on in connection with numerous saw 
mills, which furnished abundant fuel. In only a few towns are the 
old salt blocks utilized at the present time. Many regions have shallow 
flowing wells and by a combination of these two sets of well records and 
an examination of the outcrops, fairly accurate data concerning the 
surface and depth of glacial drift and the stratigraphy of the old rock 
have been obtained. 

The Coldwater shale is reached by some of these deeper wells on the 
northeastern border, possibly at East Tawas, and certainly at Au 
Sable. After considerable careful examination it is still an unsettled 
question concerning the brine of the East Tawas wells, but it seems 
quite probable that it comes off the top of the Coldwater shales as 
when this is reached under cover it is quite salty. 

The next formation lying above the Coldwater shales is the Lower 
Marshall, which is easily recognized by its abundance of red rock, 
called paint rock by the drillers. This is found in the lower wells at 
120 to 800 feet, and in its lower part it alternates with beds of blue 
shale, with the red rock growing gradually thinner at the bottom of 
the formation with a corresponding increase in the blue shale beds, 
and at 700 feet an abundance of brine in a gray sand rock has been 
found in the East Tawas wells. 

At East Tawas the Napoleon or Upper Marshall is represented by 
some 20 to 40 feet of white sandstone and is the first formation reached. 
Wherever this formation is drilled into in the county southeast of 
Tawas an abundant supply of water is yielded, while the lower forma- 
tion yields a water which is saltier. The flowing wells which are found 
at Turner, Alabaster, Au Gres, Twining, Omer, Standish, and Pin- 
conning all have wells in this formation. These wells do not pass 
through any red rock at all, and so it seems that water must come from 
the Upper Marshall or Napoleon. On Rifle river it has its only out- 
Crop, not a well exposed one, which exists near the West Branch 

The Lower Grand Rapids group or Michigan series is well known 
to the well drillers because of the prevalence of seams of gypsuin alter- 
nating with limestone layers and shaly sandstones. The water of the 
gypsum beds is always very strongly mineralized and unfit for use. 
The Alabaster quarry, Iosco county, is in this formation, as are the out- 
crops at Plaster Bluff, Cramer's Creek, Turner, Twining, West Branch 
and Glendon dam. The gypsum is not uniform in thickness, and in 
places is interstratified with many stones of hard cherty limestone, 
and in other regions, as at Turner at the small shaft sunk by Mr. 
Hand, the seams are brownish dolomitic limestone. 



The most extensive exposure of the Michigan series is at Alabaster, 
four miles south of Traverse City, in Iosco county, in the quarry of 
the North American Plaster Co. A bed of gypsum with an average 
thickness of 23 feet is covered with a stiff brown boulder clay, free from 
pebbles, 10 to 12 feet in depth. This one bed, — in reality, two beds, are 
present as in early working of the quarry a layer of hard fossiliferous 
limestone and a small layer of shale were between the two beds, which 
have entirely disappeared in the recent working. The bed has been worked 
back from its original outcrop on the shore of Lake Huron, nearly a 
thousand feet, and the face of the bed now exposed is more than a 
quarter of a mile in length. See Plates VII, VIII and IX. 

For convenience in hauling away the rock as it is blasted from the 
face of the bed, the quarry is being worked in the shape of a huge horse- 
shoe, with the face of the bed on the outside of the bow. The material 
stripped from the top by steam shovel is carried by tram cars to the 
center of the bow, making a huge dump which has somewhat interfered 
with the drainage of the quarry, but offers the least expensive method 
of disposal of this material. 

The top of the bed exposed by the removal of this heavy brown clay 
is very even, showing a slight dip to the southwest and many small 
ravines, due to the solvent action of percolatory waters, which generally 
come through the sandy streaks in the clay. 

The gypsum is removed from the surface by blasting, the charges are 
distributed in steam drilled holes, along the bed, and large masses thrown 
down to the floor of the quarry, and is here broken by handwork into 
sizes convenient for the crushers or for shipping by boat. 

The dark colored, impure gypsum with a large percentage of clay is 
utilized for land plaster. A variety which is streaked like castile soap, 
with irregular seams of clay, is shipped to eastern markets, where it is 
made into Mexican onyx. The purest gypsum is ground, heated and 
converted into familiar plaster of Paris. Many of the patent hard finish 
wall plasters and fancy l kalsomines have the calcined gypsum as their 
chief ingredient. The familiar "stucco" material is the calcined gypsum 
mixed with size or glue. The larger part of the staff material used for 
the World's Fair buildings and the Pan-American, came from this 

A 90-foot shaft was sunk several years ago by the North American 
Plaster Co. to determine the condition of the lower beds of their deposit. 
The underlying rock of the quarry is a bluish gray sandstone, alternating 
with seams of hard cherty limestone and brownish sandstone. At dif- 
ferent depths several small beds of gypsum occur, the largest one nearly 
5 feet thick, and at 85 feet depth. At 90 feet a strong flow of water 


occurred, which stopped further work, and it is quite probable that this 
represents the bottom of the Michigan series. 

In the gypsum bed no trace of organic life has been found, but in the 
early working of the quarry, before the two beds were found blending 
into one, they were separated by a small layer of shale and limestone 
from which some fossils were reported by Winchell. 

In the report upon the geology of the 'lower peninsula of Michigan 
(Geological Survey of Michigan, Vol. Ill, Pages 105-107) by Dr. Rominger, 
the bed of gypsum then exposed was only 15 feet in thickness with a 
few additional feet of shale and flagstones. The recent active quarrying 
has exposed the present gypsum bed of 23 feet, overlain by 15 feet 
of drift. 

The fossils found by Dr. Rominger were in the middle beds of flag- 
stones and the shells (which have now entirely disappeared) named in 
the order of their abundance he called: Myalina, Allorisma, Avicu- 
lopecten, Edmondia, Rctzia gibbosoa and Spirifera speciosa. 

cranner's creek. 

On Cranner Creek, which is a branch of the Au Gres river in 21 N, 
R 5 E., in Sec. 20, just west of the junction of this creek with Johnson 
creek, is a deposit of a very light rose-colored gypsum in its bed, being 
exposed in a few places for 200 feet along the creek's bottom and the 
low water of late summer months, showing large holes where the rock 
has been washed away when exposed to water action. The gypsum is 
covered by a bluish gray shale with occasional seams of arenaceous 
limestone. This is a place where some careful exploration of the high 
clay bluffs might reveal a bed of sufficient quality and quantity for 

A short distance below the junction of these creeks, at an old aban- 
doned lumber dam, the drift has been moved and shows, at low water, 
the upper layer brownish limestone of 1 foot in thickness, underlain 
by a 6-inch bed of pink-tinted gypsum, and some 8 inches of blue shale 
which rests upon a bed of white gypsum, whose exposure is not enough 
to determine its character. This seems to indicate that the workable 
bed of gypsum is below the bed of the creek rather than in the high 
clay hills which form its valley. 


In Sec. 28, T. 22 N., R. 6 E., 1-8 of a mile above the old Glendon dam 
on the east bank of the Au Gres river, is a cut which exposes the follow- 
ing sections: — 

One foot clay, 4i feet gypsum, top layers very pink; 3 in. roughly foliated lime- 
stone and sandy limestone interstratified; 2 feet of yellow shale; 3 feet of bluish 
gray arenaceous shale. 

70 QYP8UM. 

This is the only outcrop in this region in which the pink color of 
the rock is pronounced, and may be due- to the fact that this was near 
an old stream flowing into the basin when the gypsum was being de- 
posited and thus bringing some of the iron salts resulting -from de- 
composition of rock into the water. The color is very uniform and 
regular, without any indication of being formed by infiltration after 
gypsum was deposited. 

From the sink holes in the vicinity, and the fact that gypsum occurs 
in the outcrop, a company was organized several years ago and many 
tests were made by driling, but the results were not satisfactory and 
failed to show at any place a bed of over 5 feet and the gypsum was 
pronounced valueless for commercial working and was considered a 
collection of big boulders rather than an actual outcrop, but the presence 
of the blue shale in the river bed some distance below and above the 
outcrop is sufficient to establish this as an outcrop. Careful searching 
has yielded no fossils. 

On the Au Gres river, in Sec. 27, T. 22 N., R. 5 E., the river bottom in 
the southeast corner of the section is covered with a blue, grayish arena- 
ceous shale, which is so closely associated with the gypsum deposits 
of this region. Northwest, a quarter of a mile from the southwest cor- 
ner of this section, a three foot bed of gypsum occurs in bank of the 
Au Gres river. This is covered by two feet of sandy limestone and 
underlain by the blackish shales. 

Following the Au Gres river through the sections of the southeastern 
part of the above township, small beds of arenaceous shales are found. 
A number of sink holes in Sec. 36, outcrops in sections 24 and 12, are 
reported but have not been found. 

At Whittemore, in Sec. 10, T. 21 N., R. 5 E., is a well which pene- 
trated several beds of gypsum at 50 feet and 170 feet. North of Whitte- 
more, at Mr. Armstrong's house, beds of gypsum of 5 and 7 feet thick- 
ness were passed at 90 feet and 130 feet in drilling for a flowing well. 


In the S. W. % of the S. E. % of Sec. 23 of T. 20 N., R. 5 E. (Mason) 
Of Arenac county, an attempt has been made to find the thickness and 
depth of the gypsum bed. This place is due west of Twining 1*4 miles, 
and has an elevation of 648 to 652 A. T. Several small test pits were 
sunk to the rock, which was found on the average at about 8 feet cover- 
ing of drift material, largely boulder clay. 

One of these pits, on the authority of Mr. Nelson^ who assisted in 
making the tests, has the following strata, a record which, from well 
records in this vicinity, seems to be fairly accurate : — 



8 feet of clay ; 

3 feet of gray sandstone mixed with small strata of gypsum ; 
5 feet of gypsum (?), white; 

2 feet of gray sandstone mixed with gypsum, rests on 19 (1?) feet 
pure gypsum. (Very doubtful but not impossible.) 

From an examination of the material thrown out of the pits, some- 
what different conclusions might be drawn. The amounts of brownish 
sandstone and gray limestone are about equal. The brown sandstone 
being found on top with a few streaks of a very hard non-fossiliferous 
limestone. The gypsum which has been taken out contains much clay 
and resembles the poorer grade called land plaster at the quarry of the 
North American Plaster Co. at Alabaster. 

The gypsum exists in two forms, one of dark mud-colored lumps which, 
on breaking open, show inside small irregular masses of pure, white, un- 
crystallized gypsum, as if after deposition of the material water action 
had disturbed the water material and brought in much silt which has 
formed a complete covering for the gypsum. Some iron pyrites were 
observed in a large number of specimens embedded in the gypsum and 
running in seams through it. This occurrence of iron pyrites with 
gypsum has not been observed before in any of the other deposits 

A bluish argillaceous shale has been taken out in a large quantity 
and closely resembles bluish shale from Alabaster and Au Gres river. 
It is believed that this pit represents the top of the gypsum beds in this 

At Twining, in drilling the flowing well of William Lilleberger, a 
vein of gypsum was found at 25 feet, but its thickness has not been 
carefully observed. In Mr. Barr's well, on Sec. 25, which is south iy 2 
miles, a 10 foot vein of this same rock was encountered at 20 feet, and 
the water of several wells in the near vicinity is very bitter, giving 
with Ba Cl 2 solution a strong precipitate of Ba S0 4 , which indicates 
the presence of gypsum in the water. Mr. Barr states that the mineral 
comes to the surface 40 rods west of his house, but this outcrop has not 
been found. There is no question but that a bed of gypsum of fair 
thickness underlies the region of Twining, Turner and Turtle. Its 
value for working can be deterimned only by careful work with a drill. 


The formation which is exposed above the Michigan series is that of 
the Maxville limestone which usually in this area forms a slight bluff on 
the southern slope of the outcropping gypsum and in particular in the 
region of Omer, Au Gres, and if followed to the northwest, on Granner 
and Johnson creeks. The relations aid in following the boundaries of 
these two formations. 


The bed of Johnson creek in Keystone dam, in Sec. 30, of 21 N., It. r> 
E., is some 8 feet higher than the top of the exposure in Cranner creek, 
and although some of the intervening beds have not been found, the 
Keystone dam formation corresponds so slosely in lithological character 
and in fossils to the beds of Harmon City that its position in regard 
to the gypsum must be similar. 

At the Keystone dam some 800 sq. ft. of rock is exposed. The beds 
dip only slightly to the S. W. and is traversed by few joints, and the 
beds are cut nearly 10 feet deep, for a distance of 500 feet by the creek 
which was formerly dammed at this place. The following description 
applies to this formation: 

2 feet. This is the top layer and is a slight gray, brittle, slightly 
arenaceous limestone with a conehoidal fracture. Small druses con- 
taining crystals of calcite are scattered abundantly through the bed. 
Fossils, especially Allorisma, are quite numerous. Greenish stem-like 
bodies of irregular shape occur similar to some of the branching forms 
of bryozoa. The lower part of this layer is filled with flint nodules in 
shape and size like those of Harmon City, but are more cherty and of 
a darker color than those from the Lake Huron locality. 

3 feet of dark brittle limestone filled with irregular lime concretions 
which are found in the Omer quarry. These concretions, when broken 
open, show excellent specimens of calcite. 

1 foot of dark gray arenaceous sandstone or some branching forms 
of the lower forms, effervescing with weak acid and containing remains 
of some stems. 

4 feet. Beds of gray color, hard and compact and calcareous in upper 
part, very brittle in the lower part, which is more sandy and with many 
small seams of fossils and cavities of calcite crystals. 

Following the creek down 100 feet from the old abandoned dam, 
the following section occurs: — 

1 foot clay drift ; 

2 feet limestone, many fossils and nodules. Brittle argillaceous at top 
and gray arenaceous at bottom. 

1 foot brittle cherty limestone with small white streaks of chert. 

5 feet gray brittle finely laminated freestone which has a few inches of 
black shale at its top. 

4 feet sandstone of gray color in places, very probably due to weather- 
ing. No fossils. 

A point 200 feet fronj the dam another section occurs, which, per- 
haps, is more of the sandstone of this series and has the following 
beds : — 

3 feet clay drift from the surface. 

3 feet gray hard limestone with a few fossils mostly concretions like 
quarry at Harmon City. 

Geological Survey of Michigan. 

Vol. IX Part IJ Plate IX. 



6 feet bluish thin bedded sandstone or freestone resembling some of 
the grindstones with a three inch layer of black shale at top of the bed. 

8 feet, made up of 4-inch layers of bluish sandstone. Each bed in 4-inch 


All of the deeper wells which have been drilled in the village of Turner 
have penetrated a bed of more or less thickness of gypsum. The con- 
clusions which have been reached from a few tests have been that the 
beds were too far below the surface to be of practical use in commercial 
workings. All of the shallow wells dug in the till contain large boulders 
of gypsum; out of one well nearly one-half ton of these boulders were 
taken, showing the abundance of gypsum within the till. The appear- 
ance here of these boulders is due to glacial action which scrubbed off 
masses of rock, in the region of the northeast, where the gypsum out- 
crops plentifully and were thus carried by the ice in the ground moraines 
and left in this place. 

The water of most of the shallower flowing wells is strongly gypsif- 
erous. The water from the flowing well at the schoolhouse, in Sec. 8, 
T. 20 N., R. 6 E., which is east ofr Turner and gives a strong test for 
gypsum and in drilling it three distinct beds of gypsum were found 
each three feet in thickness, and the test of this water indicates that 
the bottom of the well is still in the Michigan series. 

Near the corner of Sec. 9, of this same town, Mr. Clukey drilled a 235- 
foot well and passed 8 feet of gypsum at 95 feet. In Turner, near the 
Detroit and Mackinac depot, is a well of 300 feet depth and a very 
strong flow. The record of the well shows gypsum of 5 feet thickness 
at 64 feet. Mr. M. H. Eymer of this place has a well of 105 feet depth 
and at 50 feet passed a 12-foot vein of gypsum. 

The flowing well drilled on the property of Mr. Swartz penetrated 
a 15-foot bed of gypsum at a depth of 50 feet, the covering being drift 
and brown limestone. One mile north of the Swartz property, Mr. 
Applin drilled a well and obtained a strong flow at 250 feet, striking 
a 15-foot bed of gypsum at 25 feet. 

Several years ago Albert Hann opened a 36-foot pit east of Turner, 
in the southeast corner of Sec. 8. The pit was opened with the expecta- 
tion of obtaining a large bed of gypsum near the surface, but the work 
was finally abandoned for the reason that no bed was found near the 
surface of sufficient size to be of any value in working. The following 
strata are quite typical of the underlying rocks penetrated by the wells 
in this region: — 

25 feet boulder clay filled with gypsum and occasional erratic. 
3 feet blue, grayish arenaceous shale containing small grains of undis- 
solved gypsum particles. 


% foot of gypsum interseamed with hard brown limestone. 
7 feet consisting of hard flinty limestone with many cherty layers and 
small seams of gypsum. 


Where the Detroit and Mackinac R. R. crosses the east side of Sec. 
36, T. 20 N., R. 6 E., the Michigan series are exposed for nearly 200 feet 
in the sides of the track in the three foot cut made for grade of road bed. 
The outcrop is covered by the drift in all parts of the near vicinity. 
The land at this place is formed into a distinct low ridge crossing the 
R. R. track at right angles and its prominence is perhaps due to the 
fact that it consists of the hard calcareous sandstone which occurs just 
above the gypsum at the Keystone dam, Harmon City, and in the small 
test hole on the property of Albert Hann. The exposed gypsum here is 
a 6-inch layer and several other layers of hard cherty limestone. The 
cap of these formations is a hard brown sandstone of a foot in thick- 
ness. Along the top of this ridge, which is quite pronounced in direc- 
tion, would be a place quite suitable for further exploration for the loca- 
tion of a bed sufficient for working on a commercial scale. The well 
records, especially those of Mr. Applin and Mr. Swartz, are good clues as 
to what may possibly be expected in the size of bed to be found. 

West of the track, near the center of the rather broad, low east and 
west ridge, Mr. McLean dug a small experimental pit, and from the 
material thrown out, sandstone was found in abundance, and the gray 
smooth limestone, both of which closely resemble layers exposed at Har- 
mon City on the shore of Lake Huron, and with these beds are associated 
a few small layers of gypsum. At the house of S. B. Dwyer, which is 
west of the R. R. and southwest of the low ridge, a dug well was made 
into six feet drift through 12 feet shelly brown sandstone and one foot 
of blue grayish shale. 


The gypsum beds can be clearly traced by wells to the south of the 
outcropping region as they dip to the center of the basin. This is 
especially noticeable in the deep wells of the townships of Au Gres and 
Whitney, in Arenac county. The well on the William French estate, in 
the northwest part of Sec. 6, T. 19 N., R. 7 E., has a record of 14 feet 
of gypsum at 100 feet in depth ; also the well in Mr. Coles farm reaches 
gypsum at 80 feet in depth, while south of the village the wells of Mr. 
Ullman and Mr. Silly penetrate a bed of gypsum at 100 to 115 feet. 
In the above village some of the shallow wells, like those on the proper- 
ties of Mr. Grimore, Mr. Bradley, Mr. Badour, show small streaks of 
gypsum at a depth of 50 to 60 feet. 



In Arenac county the point of contact in the Maxville limestone and 
the Michigan series is on the shore of Lake Huron, 500 feet north of 
the northeast corner of Section 24, T. 20 N., R. 7 E., and north on 
the shore of Harmon City. At this point the banks are 15 to 20 feet 
high. The entire ledge shows the effect of the lake action and the follow- 
ing section is well exposed: 

4 feet clay or till. 

3 feet red clay, with particles of lime. 

l^feet white clay. 

3 inches cherty limestone. 

5 inches of cherty limestone and sandstone closely interstratified. 
1 inch shale and brownish limestone. 

8 inches limestone. 

6 inches brown sandstone. 

4i/fe feet bluish gray sandstone. 
10 inches arenaceous limestone. 
5 feet bluish sand. 

The strata are quite irregular as the thickness of the limestone varies 
and, as Winchell has noted, the dip from the point seems to be north 
and south. 


Going north 1-8 of a mile on the lake shore from the above outcrop, 
to the old Whittemore test shaft, we find the limestones are blended 
into brownish sandstones and the layer of bluish arenaceous sandstone 
in the stratum of 1% feet thickness, which is crumpled and folded with 
thick seams of argillaceous limestone. In this shaft a 10-foot seam 
of gypsum was reported to have been found, but the project was given 
up, because of the inflowing water. From this point north on the shore 
to Alabaster, the lake sand covers all evidences of outcrops. Off shore 
from this point in 15 feet of water, are seen white beds of gypsum, 
being part of the lower bed worked at Alabaster and the one penetrated 
by wells at Au Gres and Turner. 


The following are the railroad elevations of this district above tide : 


(Old Jackson, Lansing and Saginaw B. B.) 

White Feather 604 

Saganing or Worth 622 

Standish * 625 

Deep Biver 657 

Sterling 743 

Dunham 764 

Quinns 784 

Alger 782 

Culver 787 

Summit j, 829 


Distance from 
Station. Bay City. Elevations. 

Bay City, Saginaw Bay and North- 
western Branch of the M. C. B. B. 18.6 593.33 

Saganing 25.7 592.58 

Pine Biver 29.4 595.58 

Omer 34.2 610.94 

Twining 39.2 638 

Turner 41.5 632 

Emery Junction 48.8 672 

Mclvor 50.6 664 

Marks 54.3 644 

Tawas City 59.7 587.5 

East Tawas 61.0 587.5 

Oscoda 74.3 601.5 

Alpena 126.0 601.5 

May 30, 1901, the lake level, was 7.5 feet below track grade at the 
East Tawas station. 

An old profile at the Engineer's office of the Detroit and Mackinac 
B. B. states that the elevation of grade on the south bank of the 
Bifle river below Omer is 25.36 feet which equals 20.94 feet carried 
from Emery Junction. Thus the datum of the line north from Bay 
City is 4.42 feet higher than from Emery Junction to Omer. This may 
be accounted for by the fact that the datum from Emery Junction 
south was five feet lower than the datum of the line from East Tawas 
to the Junction which was built first and continued to Alger by the 
Michigan Central. The line from East Tawas to Alger was referred 
to 580 A. T. (the level of Lake Huron at East Tawas in 1880, 
and gives Alger, according to the D. & M. profile an elevation of 781 
feet which checks with elevation obtained by the Michigan Central 
for the same place. The line from Bay City north was evidently re- 


ferred to 580 A. T., a very meager record of this fact is made in one 
of the field books of the railroad office and some point of Saginaw 
River was used as a datum. All of the above elevations are based 
upon the datum of 580 A. T., for Lake Huron. 


This road is now abandoned from Alger to Prescott, the remainder 
of the original line from Prescott to East Tawas has been consoli- 
dated with the Detroit and Mackinaw railroad. 


Alger 781 

Moffat 769 

Shearer 796 

Prescott 768 

Mills 794 

Whittemore 777 

Emery Junction 672 

The elevations are referred to the datum of Tawas Bay on May 30, 1901, 
which was taken as 580 A. T. This line of the Bay City and Alpena 
at one time connected with the Mackinaw Division of the Michigan 
Central at Alger. The elevation of Alger on the profile of the old 
line is 781 A. T., which checks with that given to Alger by the Michi- 
gan Central. 

§ 8. Huron County. 

The strata of the Alabaster district pass southeast into Huron 
county. 1 The sub-carboniferous limestones of the Upper Grand Rapids 
found in Arenac county are also found with nodules and geodes of 
chert and quartz and interstratified lenses of coarse sandstone on the 
Charity Islands and around Wild Fowl Bay. Underneath them are 
the beds of the Lower Grand Rapids Group, mainly shale with some 
dolomites and some gypsum, as shown in the geological column of the 
county given in Figure 10, a reproduction from Plate I, of Vol. VII, Part 
2. Upon the geological map of the county, Plate VII, the course of 
the point where one gypsum bed comes to the base of the drift is out- 
lined. This appears to be well marked by the character of the well 

Generally, however, there are from 20 to 30 feet of drift. Probably 
the best chance of striking gypsum under a reasonable cover is along 
the valley of the Pinnebog near Soule. Compare the wells on Sections 
7, 8, 16, and 36 of Chandler Township. Beside these references on 
pages 182 and 185, see the records at Caseville, pp. 189, 179 ; Wisner, p. 

1 See report on Huron county, Vol. VII, Part II of these reports. 


164, 167; around Tarry in Fairhaven, pp. 161-161, and p. 226. Gypsum 
evidently extends, down into Tuscola county, but I think that going 
southwest from Huron county we come toward a ridge or anticlinal in 
the Marshall sandstone which was probably formed during the early 
carboniferous time before the formation of the gypsum, and served to 
limit the extent of the gypsum on the southeast side of the coal 
basin. Here and there are patches of strongly saline shallow wells, 
but on the whole wells from Vassar and Flint to Bellevue show but 
little sign of the gypsum formation. 



Upper Marshall.. 

hqm b — ~ 

Lake clays and bowlder elays. 

Sa&datoaa, shale, eoal,aad in slay. 

Whi u a^ M ao and reea shah, with beds 

Hydranlk l i m esto n e. 

Huron grindstone. 
Bin* abate and sand abate, with 
Undto((C*r«)Co r 

Point Aui Baronet lfchtheeas. 

Port Hop* well. 

Sand Beach well. 
Rock Falls. 
White Rock wan. 
Foreatelll* waU. 

Black or chocolate ahal*. 

White to brown sandstone: Analysed, para 

Bedford bine ahala I, 50 fart. 
Cleveland black abate I, S fact. 

r_ l>k bloc or black shale, 13S feet. 

Black shale. 

Blue argillaceous limestone, Tory hard. 

Dolomite: Bitter water, 

water; analyzed. 
Sand Brach. 

by nit 

Fig. 10. Geological Section of Huron County 


§ 1. Historical. 

The town of St. Ignace is located in Mackinac county on the north- 
ern peninsula of Michigan across the straits from Mackinaw City. The 
narrow peninsula extending southeast from Upper Michigan, termi- 
nates in the point of St. Ignace just below the town of the same name. 
Small capes jut out on the east and west sides of this peninsula, and 
are known as points. The prominent ones on the west side are, Point 
Aux Chines and Point Labarde; and on the east. Gross Point and Rab- 
bit's Back Peak. Plates XXI and XXII. 

The narrow gravel and sand beach rises rather abruptly to the up- 
land bluffs covered with pine and poplar timber. The area is traversed 
by the Duluth, South Shore, and Atlantic railroad, which terminates 
at the Point and there is connected by ferry with Mackinaw City of 
Lower Michigan. 

The town of St. Ignace extends along the shore and a short distance 
on the bluffs above. Its history dates far back to the early days of 
the Jesuits. This place was an early missionary outpost and here 
is the grave of that famous priest, Pere Marquette. 

The bluff above and around the city north and south is composed 
of heavy ledges of limestone of the Monroe series, which in geological 
age is Lower Helderberg or Salina. The rocks are covered near the 
town by a mantle of drift which has disappeared in many places 
through erosion. It has been an important lumber center and attempts 
have been made to develop a salt industry. St. Ignace is reached by 
steamers from Chicago, Detroit, and other lake ports. The distance 
from Chicago is 330 miles. 

An early account of the gypsum deposits at St. Ignace is given by 
Dr. J. J. Bigsby (the eminent geologist, after whom the Bigsby Medal , 
was named). Dr. Bigsby was surgeon at Fort Drummond and in a 
paper read Feb. 1st, 1823, entitled "Notes on the Geography and Geol- 
ogy of Lake Huron," published in the Transactions of the Geological 
Society (p. 193) he says: "At the isles of St. Martin, however, we find 
a large deposit of gypsum. It is an extensive bed of the granular 
kind, white, gray, and brown, interspersed with frequent masses of 

Geological Survey of Michigan. 

Vol. IX Part II Plate X. 




red, white, and brown selenite, occurring in shapeless lumps, in veins, 
or in small and very thin tables, having three or more sides and sharp 
angles." This account is the first found of the occurrence of gypsum 
in Michigan. 

In the 50's there was a gypsum quarry opened on the west side of 
the peninsula, seven miles west of St. Ignace near Point Aux Chenes, 
and a dock was built for loading the gypsum on boats carrying the 
rock to Chicago, where it was calcined. A scourge of smallpox caused 
a temporary abandonment of the work, and water in the quarry was 
a continual source of trouble. It was worked in an interrupted way 
for a number of years, until an ice gorge carried away the dock and 
the quarry was abandoned. The property is now owned by Chicago 
parties, but no work has been done for many years. 

About 1894 the Keystone Plaster Co. of Chester, Penn., drilled some 
test holes two miles west of the old quarry. The records of this work 
seem to have been lost, but it is stated by some of the men engaged 
on that work that <>0 f««H in all of gypsum were found in these 
wells, and the first ledge of a few feet in thickness was struck under 
a light cover. No development has followed this drilling. 

§ 2. St. Ignace Wells. 

In 1888 the Mackinac Lumber Co. drilled a well at the edge of the 
town of St. Ignace, which was UV.) feet dee]), and no gypsum was recog- 
nized in the upper layers. 

Mackinac Lumber Co. Well. 1 


sawdust, clay. 



red and blue shales (probably gypsiferous, L.). 



limestone, traces of gyjMum. 




The shales, 500 feet thick, belong to the Monroe, and iho 400 fe«*t 
of limestone l>elong to the Niagara, with possibly the Medina or Ilills- 
boro sandstone below. 

A few years ago a new well 1 was drilled two miles north of the old 
one. This is located in Heel ion :tl. T. 41 X., H. 1 K., and about 000 feet 
north of the town line close to the lake. 

iMIch. i>ol. Survey. Vol. V. Plate LXIII. 

SAnniml Report of Mich. (JeoL Survey. 1901, pp. 227. -J?*. 



The record may be summarized as follows: 

Pleistocene 34 Surface. 

11 45 gravel with gypsum. 

129 174 dolomite and shales. 

13 187 gypsum. 

68 255 red and blue shales. 
Monroe \ 5 260 gypsum. 

69 329 red and blue shales, gypsum at 300. 
97 426 blue shales, some gypsum. 
18 444 gypsiferous dolomite. 
66 510 dolomite. 


i 510 1020 dolomite (water flowing). 
J 90 1110 limestone 

56 1166 dolomite. 

Some gypsum was found at 35 feet, and 13 feet of gypsum were found 
at 174 feet, 5 feet at 255 feet depth, and more or less gypsum at other 

§ 3. Babbit's Back. 

Four miles north of St. Ignace is a prominent spur of limestone 
bluffs extending into the lake and known as Babbit's Back. It is 
clearly visible from the town from which it is separated by a half moon 
bay. Plate XXII. The bluff, composed of a magnesian limestone, which 
appears to be unfossiliferous, rises over 200 feet above the lake water, 
and shows marked effects of erosion. There is practically no drift 
cover, though granite boulders are common at the foot of the bluffs 
and on the slopes. A few years ago two kilns were operated here 
making lime from the stone above. 

In 1892, Mr. Chamberlin, the owner of this land, had five holes 
drilled with a diamond drill under the supervision of Mr. Wm. S. 
Ghalker, who has furnished me with the records of this work. 

In well No. 2, the following rocks were found : 

23 feet clay, limestone and some gypsum. 

9 " limestone. 

21 " white gypsum. 

3 " shaly limestone. 

9 " gypsum. 

These wells were drilled on the land below the bluffs in an area of 
70 acres, and about 10 to 15 feet above the water level in the lake. 
They all showed abotit the same order and thickness of the rocks. The 
gypsum in this point outcrops near the water's edge and can be seen 
under the water near the shore. At other places it is covered by about 
14 inches of dirt. 

Drilling was also done on the tract adjoining the Chamberlin land 
and gypsum was found. It was estimated that the gypsum area in this 
region would include about lfiO acres. Gypsum was found at Gross 
Point four miles north of ^abbit's Back, and its outcrop is seen near 
the shore from this point en to the east for several miles. The gypsum 


is fairly white, and in places it is spotted with dark selenite crystals 
rounded in outline. 

Similar crystals were found included in some of the Kansas rock 
gypsum, and their formation was thus explained by Ha worth: 1 

"The existence of such phenocrysts (or crystals) indicates that the 
ocean water was at one time evaporated very slowly, and under the most 
favorable conditions for the production of individual crystals. Later 
there was a slight freshening of the water by surface drainage entering 
the concentrated lake, so that a partial redissolving of the crystals was 
effected, as shown by the rounded edges of the crystals. Still later there 
was a rapid evaporation of the water, precipitating the massive gypsum, 
and an agitation of the shallow water sufficiently vigorous to mix the 
crystals already formed thoroughly with the new precipitated gypsum, 
forming the whole mass as it now appears." 

§ 4. St. Martin Island, etc. 

Some gypsum exploration was carried on a few years ago on St. 
Martin Island to the east of Rabbit's Back, and the rock shows in 
the water and was found in shallow wells over a large portion of the 
southern part of the island. The rock by analysis shows 98 per cent 
of gypsum, and so contains very little impurity. The records at hand 
would indicate good deposits which could be worked to advantage if 
the water could be kept down in the mines at a reasonable cost. The 
rock on St. Martin Island is stated to be three feet thick in the ledge 
close to the surface, with other layers further down. 

The objections to the St. Ignace gypsum deposits, that they are in 
thin veins and of poor quality, are apparently untrue. The evidence 
at hand does not accord with these rumors. The price of fuel might 
prevent the manufacture of plaster in this section of the State though 
water transportation is available, but the gypsum might be mined 
and shipped to other points further south. At the present time there is 
no development of these gypsum fields. [It is probable that gypsum 
occurs not far beneath the surface in the northern islands of the Beaver 
Island group. I hrfve seen many indications of it. L.] 

•University Geol. Survey of Kansas, Vol. V, p. 



§ 1. Preliminary. 

A large number of wells have been drilled in this State in search for 
water, salt, oil, and gas. Many of the records of these wells have 
not been preserved, but a considerable number have been printed in 
the reports of the State survey. In these reports it is not always pos- 
sible to identify the formation. An examination of published records 
shows the Michigan series identified in 24 wells. 1 

A comparative study of the records preserved will throw some light 
on the distribution of the Michigan group of rocks, and the places 
where gypsum 3 is to be found and at what depth. A study of the under- 
lying sandstone will throw light upon the nature of the iloor of the old 
sea, from which the salt and gypsum were precipitated. 

The gypsum deposits of Michigan at Grand Kapids and Alabaster 
are found in the Grand Kapids division of the Michigan group, which 
is Carboniferous in age. The deposits at St. Ignace are in the Salina 
formation. In the wells in Monroe county and some others in the State 
gypsum is found in this same formation. The first division of this 
chapter will be devoted to the study of the gypsum in the Carboniferous, 
and the second to the deeper deposits of the Salina. 

In most of the wells, the first formation on the surface is the drift, 
consisting of sands, clays, and gravel. The records which follow have 
been taken mainly from the published reports of the Michigan survey, 
but have been condensed and adapted to the present purpose. The 
levels given are railroad levels of the nearest points, and so are not 
always accurate for the top of the well. 

$ 2. Carboniferous (Grand Rapids Group) Gypsum. 

The distribution of the Grand Rapids group below the surface can- 

lViz.: Alma. Vol. V. Pt. 2. p. 45. Vol. VIII. Pt. 2. p 175: Bay City. Vol. V. Pt. 2. Plate VI, and 
annual for 1901: Caseville, Vol. V. Pt. 2. p 53: Vol VII Charlotte V. Pt. 2, VIII; Corunna V. Pt. 2, 
Plat** XTl: Rast Sojrlnnw V. Pt 2. p. 55: South Saplmiw and the Bliss well. VIlT.Pt. 2, p. 176: Grand 
Rapids V. Pt 2. p. fll: Kawkawlln V. Pt. 2. p. tt>: Midland V. Pt. 2. p. 6P. VIII, Pt. 2, p. 163: Sebe- 
wain? VIII, Pt. 2. p. 172; St. Charles VIII. Pt. 2. p. Wl: St. Johns VIII, Pt. 2, p. 196: Durand VIII, 
Pt. 2. p. 19fr Mason VIII. Pt. 2. p. 217. 

-It is worth noting that microscopic observations lead me to believe that all the calcium sulphates 
below, say 500 feet, is really in the denser form of anhydrite and water rather than pypsum. 
This is to be understood in reading the description. When anhydrite is mentioned it is because I 
have actually recopnized it as such under the microscope. I have also inserted some newer data 
retfsirdinp Mt. Pleasant. Detroit, Wyandotte. Milan. Ludintfton. Muskegon, etc. L. 


not be described over very much of the State of Michigan on account 
of the small number of well records available. The farthest north this 
group is found in recorded wells is at Grayling in Crawford county, 
125 miles northeast of Grand Rapids. The formation in the Grayling 
well consists of sandstone, limestone, shales, and gypsum, 175 feet 
thick as compared with 177 feet in the Lyons well at Grand Rapids. 
The gypsum is 408 feet from the surface, where the level above tide is 
about 1,135 feet. It is reported as 132 feet thick, but there is but one 
sample, and this is doubtless incorrect and the thickness includes 
shales. This record would place the gypsum 727 feet above sea 
level, while at Grand Rapids it is 530 feet in the Lyons well. At Gray- 
ling the Grand Rapids group rests on the Coldwater shales. 

A general theoretical section of the Lower Michigan rocks is as follows: 


Drift. . . , 3 to 60 

Saginaw (Jackson) Coal Group (Upper Carb.) 50 

Parma *• '• 100 

Grand Rapids Group Lower *• ... t 300 

Marshall sandstone ) i 75 

Coldwater shales, etc. > ( Waver! y ) j 800 

Berea sandstone ) ( 65 

Antrim shales (Devonian) 225 

Traverse Group (Hamilton) 350 

Dundee limestone ( Devonian) 100 

Monroe beds (Lower Held, and Sitlina) 700 

The Grayling well record may be summarized from the Annual Re- 
port of Michigan Geological Survey, 1901, page 232, as follows: 

Drift 3*55 feet drift gravel, etc. 

j 380 " 15 calciferous sandstone. 

T ,-• a i> • i 408 hi 28 dark limestone. 

Lower Grand Rapids^ 540 » 132 gypsum and shales. 

[ 960 " 420 blue shale. 

CnldwMUM- J 1150 " 1W> limestone. 

Colduatei | 154() t4 39Q blue bhale . 

Berea (?) 1500 " 50 red and blue shales. 

Devonian 2750 '' 11()0 shales and limestone. 

On the eastern side of (he Lower lVninsula are found the records 
of the East Tawas well, those of Huron county already referred to, 
and the group of l'ort Huron wells at New Baltimore, St. Clair and 
Marine City. Iu (he Tort Huron group of wells, the Pleistocene rests 
on the Devonian, with no traces of the Carboniferous strata. The 
gypsum (anhydrite?) comes from the Monroe (Salina) rocks. At East 
Tawas 50 feet of drift res(s on the Marshall sandstone with no (races 
of the Grand Bapids group. In the Sebewaing well of Huron county, 
56 feet of drift rests on 44 feet of the coal measure sandstone and 
shales. The Grand Bapids group, 100 feet below the surface, consists 
of shales and limestone with no gypsum beds, and rests on the Marshall 
sandstone, which is 248 feet below the surface. (See the Huron county 



report, Volume VII, Part 2.) But the wells for Terry, the next station, 
and thence north, show more or less gypsum. 

In the Saginaw and Bay City area there have been numerous wells 
drilled in search for salt, and out of the large number a few records 
are available. At Bay City the Grand Rapids group lies below 100 
feet of drift and 465 feet of Jackson coal shales. It consists of lime- 
stone, sandstone, shales, and gypsum in a 12 to 15 foot layer. The 
gypsum is 712 to 720 feet below the surface and 128 feet below sea 
level. Below the Grand Rapids group comes the Marshall sandstone 
and Coldwater shales. 

The Bay City well record (a newspaper record) given in Volume V, 
is as follows; down through the Grand Rapids series: 


Saginaw coal measures 

Grand Rapids series 

Lower Grand Rapids or 

120 120 


1 50 






limestone, 852 brine, 
sand rock. 

sandy shale, 
blue shale. 

gypsum, 1 white 6- inch casing to 
722 feet. 1 

( 108 820 blue shale. 
Marshall, upper ■< 10 830 hard limerock. 

( 80 920 sandstone, brine 100.° 
Marshall, lower 135 1055 red and white shale and so on down to 

2865 feet. 

The well at the North American Chemical Co.'s works, So. Bay City, 
was given in the Annual Report for 1901, p. 224, as far down as the 
Marshall, and is as follows, revised: 




sand, clay, etc. 

Saginaw coal measures 



shale, quicksand, and Bait. 

Parma ? 



sandstone pyrite at top. 




Upper Grand Rapids 




( 5 








gypsum, etc. 



limestone 10, shale 10, sandstone 10. 



gypsum (compare 712 of 1st well). 

Lower Grand Rapids 



" and limestone. 
" " shale. 



shale and limestone. 



limestone, gypsum shale. 



limestone and shale. 



pyritic limestone. 

Upper Marshall, 




water-bearing sandstone. 

Lower Marshall 



sandstone and shale largely red. 

Coldwater. 2 




Goes on down to 3508 feet. 

'Or anhydrite. 

^Compare with Saginaw wells, like Whittier's No. 3, which when abo Jt 740 feet deep was cased 
down to 551' 2". 


It appears that beside other gypsum beds, one near the bottom, there is 
a quite persistent bed 130 feet or so above the bottom. A bed in a sim- 
ilar position is found in Huron county, at Midland, Alma, and Mt. 
Pleasant, so that it is probably quite persistent. 

At v Kawkawlin, just north of Bay City, the drift is 100 feet thick 
and the Jackson Coal group 300 feet. Gypsum was found at 400 feet 
and the thickness of limestone and gypsiferous shales was 100 feet. 
This record is incomplete, but probably shows the Marshall sandstone 
below. The gypsum is 196 feet above sea level, and farther north at 
Alabaster it is about 600 feet above the sea. 

Abstract of Kawkawlin Well, Bay County. 

Michigan Geol.. Survey, Vol. V, p. 65. 

Drift 100 drift. 

Jackson Coal 

Measures 400 300 shale, sandstone, coal seams. 

Grand Rapids ( 500 100 limestone, shales, gypsum at 400 feet. 

Group { 700 200 gypsiferous shales. 

Marshall ? 800 100 sandstone. 

Abstract of South Saginaw Well. 

Michigan Geol. Survey, Vol. VIII, p. 176. 

Drift 340 Drift. 
Saginaw Coal 

Measures 493 153 sandstone, shale. 

Upper Grand { 525 32 sandy limestone. 

Rapids ( 555 20 impure sandstone. 


Lower Grand ( 570 75 calcareous green shale. 

Rapids or < 665 95 green shale. 

Michigan ( 690 25 argillaceous dolomite. 

Marshall 715 25 sandstone. •* 

At South Saginaw the Grand Rapids group is 493 feet below the 
surface or 95 feet above sea level and consists of limestones and shales, 
and the same order seems to hold in the East Saginaw well, where 
the group is 398 feet below the surface and consists again of sand- 
stone and shales, with some limestone and no beds of gypsum men- 
tioned. 1 

East Saginaw Well. 
Michigan Geol. Survey, Vol. V, p. 55. 


206 alternating sandstone and shale. 

64 alternating limestone and sandstone. 

172 alternating shale and sandstone. 

163 sandstone. 

3 bright red shales. 

'Though from the casing down to cut off the gypsum bearing brines it is probable that more or 
less is present, and Mr. John Coryell tells me that such is the case. For instance the Wnittier well 
at Florence 740' 11" deep was cased with an offset down to 551' 2" to keep out the gypsum, or gypsif- 
erous brine. L. 



Saginaw Coal 







1 797 

Marshall * 




Midland Well. 
Michigan Geological Survey, Volume VIII, p. 163. 
Drift 285 drift. 

Saginaw Coal 

J 920 
) 970 


sandstone, shales, 


( 1050 
\ 1130 
( 1205 


plaster red, fairly pure anhydrite 

calcareous shale. 





white sandstone. 

To the south of Saginaw, in Shiawassee county, there are three 
records available. . In the Owosso well the Grand Rapids group was 
found 473 feet below the surface and 272 feet above the sea. It con- 
sists of 83 feet of limestone, shales and thin beds of limestone, and it 
contains salt water but no beds of gypsum. In the Corunna well the 
Grand Rapids group was found at 649 feet, or 127 feet above sea level, 
and included 152 feet of sandstone and shales with no beds of gypsum. 

Corunna Well. 
Michigan Geological Survey, Volume V, Plate XII. 


Saginaw Coal 



Marshall ? 

30 drift. 

225 255 alternate shales and sandstone. 

649 394 sandstone. 

706 57 sand, shales. 

738 32 blue shale. ■ 

743£ 54 sandstone. 

744 1± black shale. 

745 1 shale. 

755 10 sandstone. 

765 10 shaie. 

800 35 sand, blue shale. 

907 107 sandstone, shale. 

Owosso Well. 
Michigan Geological Survey, Volume V, Plate XLV. 


Saginaw Coal 


Rapid s 


100 drift, 

301 201 clays, shale, sandstone, coal 

473 172 

476 3 

533 57 

536 3 

541 5 

556 15 

601 45 

716 115 

1000 2*4 

sandstone . 

blue shale, 
brown limestone. 

salt (water ?). 
soft shale. 

sandstone and salt water. 

shale, sandstone, salt water, 

The Durand Well, given in Volume VIII, Part II, p. 199, is not safely 
to be interpreted. No gypsum was recognized by the drillers. It is 
said to be mainly shale below the drift. 



West of Saginaw, in Gratiot county, at Alma, the Grand Rapids 
group is found in 790 feet and consists of 225 feet of shales and shaly 
limestone with beds of blue and white gypsum at 860 feet or 105 feet 
below sea. This is the second record showing the gypsum below sea 
level, the other being the Bay City well described above. Calcium sul- 
phate occurs at Mt. Pleasant and St. Louis, being probably anhydrite in 
all these wells. An analysis of the drillings from tjie Mt. Pleasant well 
gave M. A. Cobb of the Lansing high school : 

Per cent. 

FeA, ALA 1.4 

Ca C 3 2.83 

MgO 2 

CaS0 4 87.15 

Si0 2 , CO, and ) 8 42 
Moisture j * 

Alma Well. 


Michigan Geological Survey, Vol. VIII, p. 175. 

475 drift. 

Saginaw Coal 



shales, sandstone, some coal. 


( 860 
\ 895 




blue and black sandy shales. 

blue and white (anhydrite) gypsum. 

argillaceous limestones. 




sandstone and shale. 

Berea shale 



black shales. 

• ; *. " Berea grit absent. 

• m Z Antrim 
7-7 shales 



blue shales, 
black shales. 




limestone and shales. 

"" Good samples of the new wells for bromine of the Midland Chemical 
Co., at Mt. Pleasant, were saved. The elevation of the well is about 
770 A. T., and the anhydrite is most abundant from 450 to 600 feet 
down, the record of the well being: 
















gravel, glacial overwash. 

blue till. 


blue till. 

porous bed with water, coarse gravel on top, fine sand 

red clay, 
ground moraine till with broken coal measures. 






















Saginaw Coal Measures. 

185 620 black shale with streaks of coal (41C, 435 , 460') sand- 

stone, limestone, or carbonate of iron and fire clay, 
mostly less than five feet thick. 
90 710 Fine white sandrock with mineral water. 
80 790 gravelly sandrock with a strong flow of water, not 

so salt. 
30 820 shale and red limestone. 

Parma and Maxville. 

30 850 white limestone. 

120 970 white sandstone with very salt water. 

55 1025 white limestone fiercely effervescing. 

Lower Grand Rapids or Michigan Series. 
5 1030 shale. 

dolomite and shale, 
anhydrite and dolomite. 

" nearly pure (gypsum), 
dolomite, shale and anhydrite, 
sandstone, dark with heavy brine. 

To the south of Charlotte, in Eaton county, I recognize, in Vol. V, 
the Grand Rapids group, with some doubt. Only a few samples were 
saved, and those do not show any typical beds, though the Upper Grand 
Rapids or Maxville limestone crops out just south at Bellevue. It 
may be absent, for we are approaching the margin of the basin where 
there are variations due to irregular erosion. 

A deep well at Assyria, 917 A. T. (Sec. 4 T. 1, N., R. 7 W.) shows two 
samples which were supposed to represent the rock from the bed rock 
surface at 162 feet to 240 feet, which are typical of the Michigan series, 
dark colored dolomites, with greenish shale and some selenite. 

The reference of part of the Ann Arbor well to the Michigan series, 
by A. Winchell, 1 is certainly erroneous, and I am inclined to think that 
in the records of Jackson wells, given in Vol. V, the Grand Rapids 
group may be really absent, the heavy sandstone beneath the coal 
measure representing the shoreward coming together of the Marshall 
and Parma, as explained in Vol. VIII, Part 2, pp. 39 to 40. 

The Ludington well, given as Plate XXIX of Vol. V, is an error. 
Mr. E. D. Wheeler says it is merely his correlation of their Manistee 
well. It may have been used in Ludington as a guide to the driller in 
putting down their well. A well was recently put down by the J. S. 
Stearns Lumber Co., and a good set of samples saved for us. A lime- 
stone facies like that of the Grand Rapids occurs between 576 and 
650 feet, but similar rocks with some selenite occur in Muskegon 
wells, for instance, that of the Central Paper Co. from 625 to 850 feet 
down, which appears to be distinctly in the Coldwater series. I take 
it, therefore, that there were forerunners of the Michigan series formed 

» Vol. v, pt. 2, p. 4a 


somewhat earlier along the margin of the Michigan basin, as a fades 
of the Coldwater series. 

§ 3. Well Records Near Grand Rapids. 

In the area near Grand Rapids there have been in past years a num- 
ber of wells drilled in search for salt. Most of these wells start on 
the Grand Rapids group or pass into this formation through a shallow 
drift cover. These wells were drilled from 1840 to 1860, and the records 
carefully preserved by Prof. Winchell. In the so-called artesian well 
the plaster rock was found 57 feet below the surface and mixed with 
clay shales. The Lyons well record is given in a very detailed section 
and shows alternating shales, sands, and gypsum of the Grand Rapids 
Group resting on the Marshall sandstone. In the State well the gypsum 
was 40 feet below the surface. In the Scribner well the stratum ap- 
pears to be replaced by gypsiferous shale and the same is true in the 
Powers and Martin wells, one-half mile north of the Scribner well. 

Artesian Well Co. Well. 
Michigan Geological Survey, Vol. V, Plate XX. 





black shale. 





plaster rook, shale. 







shales, sandstone. 












shales 67 feet and dark limestone. 


j 2200 


limestone, light above, dark below, 



gas, marl, limestone, brine. 

record of the 

> same well furnished by the Godfrey Estate. 


gravel, clay. 



gypsum and shales. 












blue clay shale. 















red clay. 












limestone, sandstone, with salt. 


State Salt Well. 
Report of Winchell, I860, p. 144. 

Drift 40 drift. 

Grand ( 47 7 gypsum. 

Rapids -! 48 1 limestone. 

Group ( 61 13 clay, shale. 

Marshall 473 412 clays, shale, sandstone. 

Grand Rapids No. 2 or Lyons Well. 
Michigan Geological Survey, Vol. V, Plate XXI. 





hard gray limestone 






blue clay. 

clay with gypsu B 





clay shale. 






clay shale. 






clay shale. 



blue sandstone. 



blue" clay . 



sand and claw 



limeston e , gypsum. 






clay shale. 



sandstone, clay. 






clay shale. 



gypsum shale. 






clay, sand gypsum. 



clay rock. 




Scribner's Salt Well. 
Winchell Report, I860, p. 146. 


! 52 

1 54 
{ 204 




compact shale. 

blue limestone. 

shales, lime, sandstone, gypsiferous 








Powers and Martin Salt Well. 
Winchell Report, 1860, p. 147. 








shale, clay. 



clay, streaks of gypsum 



shale gypsiferous. 






gypsiferous shale. 






shale with gypsum. 





Marshall ? 


Marshall ? 




Indian Mill Creek Salt Co. Well. 
Winchell Report, I860, p. 149. 




























gravel, sand, 
white gypsum, 
clay, shale. 

hard rock. 





sandstone (bottom of Power's well). 

gypsum, clay. 


clay and shale. 

clay, sandstone. 

Butterworth Salt Well. 
Winchell Report, 1860, p. 148. 








clay shale. 






calcareous sandstone 



clay, limestone. 



brown limestone. 



shales with gypsum. 



lime, gypsum. 









sandstone, shales. 



shales, sandstone. 

Windsor Salt Well. 
Winchell Report, 1860, p. 150. 




f 64 





dark shale. 






shale, gypsum. 






shale, gypsum. 

1 108 


greenish clay, shales. 

i 132 


gypsum, shales. 

1 152 


blue and black shales. 

1 156 


black shale. 

j 166 


I 179 


gypseous clay, very salty. 


. 4 

black bard rock. 

1 240 


dark Hint clay, gypsum. 

( 248 


pyritiferous rock with gypseous clay 






clay, sandstone. 






argillaceous sandstone. 




Beyrich Brewery Well. 
Michigan Geological Survey, Vol. Ill, p. 110. 










blue shales. 






shales, pyritiferous rock 


















blue shale. 



hard flinty rock. 



blue shale. 





pyritiferous rock. 



white sandstone. 



blue shale. 

In the Windsor well north of the city about 30 feet of gypsum in all 
was found and the first was struck at 76 feet or 529 feet above sea 
level. In the Butterworth well in the city, the first gypsum was found 
at about 70 feet or 533 feet above sea. In the Lyons well in the city 
40 feet of gypsum were found and the first at 545 feet above sea. The 
wells south of the city, the State Salt well and the Godfrey well, 
reached the gypsuam at 596 and 620 feet A. T. 

These wells, studied in connection with the quarry exposures of 
gypsum, show that the gypsum surface is exceedingly irregular. It is 
highest north of the river and lowest in the city and north of the city. 
South of the river the gypsum dips northeast about 40 feet from the 
quarries south of the city to the wells in the city, or about 25 feet to 
the mile. The gypsum surface in the city and north beyond the city 
limits in the Windsor well appears to be almost level. If it ever 
seemed advisable to mine this gypsum in this area there would be 
trouble with water which would have to be removed by strong pumps. 

§ 4. Drilling by the Pittsburg Plate Glass Company. 

In the spring of 1902 the Pittsburg Plate Glass Co., having secured 
a tract of land north of the Grand River and west of Grand Rapids, 
drilled six wells in search for the gypsum rock (see Plate XVII). The 
results of this work have been kindly furnished to the writer by this 
company, and the following account is based on the careful notes of 
their engineer, Mr. J. J. Mears of Grand Rapids. 

The work demonstrated the existence of a good stratum of gypsum 
suitable for the manufacture of plaster, but the company decided not 
to develop the tract at the present time. The well records show the 
clay, shales, limestones, and some sandstone of the Grand Rapids 




Well "A." 

Well "B." 


sand and clay. 


sand, clay, gravel. 









flinty clay. 
















































sandstone and 




gypsum streaks. 
































blue clay. 



Well "C." 

Well "D." 


sand and gravel. 


gravel j sand. 















shale 1 . 



shale, some gypsum. 










8 hale, some gypsum. 





103 ' 








shale, some gypsum. 

Well "E." 

WeU "F." 




sand, gravel. 


















clay, pyrite. 





















inches, shale. 












sandy shale. 



. gypsum. 



inches shale. 
















In well "A v the ten foot lodge of gypsum was found at 95 feet or 
574 feet above tide. In well "IV about 100 yards east of "A", the 12 
foot vein was 123 feet below the surface, or 613 feet A. T. 

In well "D," one-fourth of a mile north of U A, V the 14 foot stratum 
of gypsum was reached at a depth of 103 feet or 594 feet A. T. In well 
"E," 200 yards southwest of "A," the 15 foot ledge was struck at 77 
feet or 565 feet A. T. In the well "F, v one-half mile north of "B," 
the 13 foot gypsum stratum was found at 123 feet or 609 feet A. T. 

Those records give a dip of four feet north in one-half mile or eight 
feet to mile from "IV to "F." The extremes of variation are shown 
in wells "B" and "E," giving a difference of 48 feet in about 600 feet. 

Geological Survey of Michigan. 

Vol. IX Part II Plate XII. 



1 16 


•. ■ • W 1 if 

^^ | 



These drillings prove the gypsum to extend over the area to the west 
and northwest of the gypsum mines now opened north of the river. 
This field will doubtless be opened before many years, adding to the 
production of the plaster in the Grand Rapids area. 

§ 5. Gypsum in Wells Reaching the Silurian. 

The gypsum deposits in the Monroe or Salina near St. Ignace are the 
only ones in this formation in Michigan found near enough to the sur- 
face to afford any encouragement for working. Possibly the northern 
islands of the Beaver Island group would find it a short way down. 
In most of the deep wells of the State around the border of the coal 
basin, gypsum or rather anhydrite is found in this same geological 

In the Niles well in Berrien county, in the southwestern part of the 
State, a 20 foot stratum of anhydrite and gypsum was found in the 
Monroe formation at 615 feet from the surface down to 720 feet. At 
the east gypsiferous shales were struck at 648 feet in the Port Huron 

Gypsum, or rather anhydrite, occurs in the Benton Harbor well at 
815 feet, and in the Kalamazoo well at 1,500 feet, in the Manistee well 
at about 1,800 feet, in the Marine City well at 1,400 feet, in the Mt. 
Clemens well at 980 feet, in the Muskegon well at 2,350 feet. Gypsum oc- 
curs in the wells of the Edison Illuminating Co., near Ft. Wayne, Detroit, 
on down from 900 feet, in the Wyandotte wells from 590 feet down (espe- 
cially at 750 feet), near Trenton from 690 feet down, at Ludington about 
2,050 feet, at St. Clair at 1,510 feet, at Milan, 1.050 feet (at 1,210 feet very 
solid). All these deposits were in the Monroe or Salina formation. 

The total quantity of calcium sulphate in the rocks of Michigan, 
from the surface Carboniferous to the deep Niagara, must be very 
great, but the deep strata of anhydrite are of only scientific interest 
and not of present economic importance. 

§ 6. Conclusion. 

A comparative study of these well records, from the various locali- 
ties of the Lower Peninsula, shows that the gypsum is found in the 
wells on the eastern and western sides of the interior coal basin and 
at the north in the Grayling well. In the wells in the interior jrypsum 
is replaced by anhydrite. The gypsum w r as evidently deposited on 
the borders of the old interior sea. 

The depth of the anhydrite in most of these wells (Bay City, 700 
feet; Kawkawlin, 400 feet; Midland. 970 feet; Alma, 895 feet; Mt. Pleas- 
ant, 1,125 feet), would be too great to make any mining profitable. 
Moreover it is a question ju^t what treatment would be needed to 
make anhydrite (which corresponds to a dead burnt plaster) set. 

98 GYP HUM. 

The industry will be confined to the eastern and western parts of 
the Peninsula, to Alabaster and vicinity at the east, and to the area 
around Grand Rapids at the west. New borings and extensions will 
doubtless increase the productive areas in these two localities as il- 
lustrated by the recent work of the Pittsburg Plate Glass Co. at Grand 

§ 7. Total Quantity of Gypsum Available in Michigan. 

On account of the irregular distribution of gypsum, being cut out 
here and there, and the uneven thickness, and the few borings re- 
corded, it is impossible to give any accurate figures as to the amount 
of gypBuni present in the two localities where it is now worked. 

There are approximately six square miles of gypsum area near 
Grand Rapids, with an average thickness of 10 feet. A cubic foot 
of gypsum weighs 140 pounds, so this area would yield nearly 118,000,- 
000 tons of gypsum, which would make about 100,000,000 tons of 
plaster. This quantity would supply the whole United States for 170 
years or more at the present rate of consumption. The Alabaster field 
would yield about 20,000,000 tons, not counting unprospected areas 
west. But little can be said as to the areas in Huron county and 
around St. Ignace. The amount of gypsum or anhydrite shown by the 
deep drill records would have to be reported in billions of tons. While 
these figures may be too high, they are yet of value in giving some idea 
of the quantity of available supply, even if the actual prospecting work 
should cut them down. 

§ I. < i rand Kapids District. 


The gypsum mine of the Alabastine Co. was opened in 1876, at the 
present locality, two miles south and one mile west of the center of 
the city of Grand Kapids. It is just outside of the city limits in the north- 
western quarter of section 2, Wyoming township, three-quarters of a 
mile south of the Grand river and on the Pere Marquette and Pennsyl- 
vania railroads. Plate V. 






Lit* t Stent 



Fig. 11, Section in Alabastine quarry, also (b) one showing uses. 

A geologic section at the mine is represented in Figure 11. The gravel 
cover is usually shallow and will average about one foot over the bluish 
shales which weather to a buff color and are 12 to 17 feet in thickness. 
Between this shale and the six foot ledge of gypsum is one foot of dark 
shale of very different character from the buff shale which makes poor 
brick and cement. As the buff shale is used for cement manufacture, 
this dark shale represents the waste in stripping. The six foot gypsum 
layer is separated from the so called 12 foot layer (in reality 11 foot) by 
about one foot or less of shale. The bottom rock of the quarry is a com- 

100 GYPSUM. 

pact bluish gray limestone which in places is distinctly banded and on 
weathering becomes soft and shaly. It seems to contain a considerable 
amount of alumina or clay. 

The gypsum is worked in an open quarry by stripping off the over- 
lying shales, and the lower 12 foot ledge is the one used at the present 
time. This ledge while slightly furrowed by solution on the top is ap- 
proximately level and has probably been protected from marked solution 
by the overlying gypsum and the compact shale. The ledge is marked by 
two thin clay seams, one about three feet from the top and another about 
two feet below this, which run into slightly wavy lines through most of 
the quarry and represent a slight change in conditions at the time the 
gypsum was deposited, a slight interruption in the precipitation, pos- 
sibly by intlowing water bringing a slight amount of sediment, or by the 
action of the currents distributing some foreign material. 

The base of the gypsum for two feet from the bottom is colored red or 
pink and rests on a peculiar cone in cone red gypsum layer four inches 
thick, called pencil rock by the quarryman. In many quarries crystals 
of selenite are found, but in this quarry I found no traces of crystals, 
though some imperfect crystals have been found but these are rare. No 
specimens of white fibrous satin-spar were found, though the cone in cone 
structure may represent a variation of the fibrous satin-spar, as explained 
in the section on the Grandville quarry. A well defined jointing plane 
runs east and west through the south side of the quarry and stands out 
clearly on account of its very smooth face exposed for a distance of 
200 feet. Minor jointing faces extending a short distance are also found 
in the quarry. 

At the north side of the quarry the gypsum is entirely cut out for a 
space of 100 feet east and west and running off to the north. The space 
is filled with clays similar to those found above the gypsum. No strati- 
fication is seen in the clay, and it has probably settled as the gypsum was 
removed by solution. The gypsum abutting this clay is worn into furrows 
and ridges of irregular course, several inches in depth, clearly the result 
of water action. In no part of the quarry are evidences of solution more 
marked. It would seem as though there must have been at a former time 
an underground water channel running through this part of the quarry 
to the north, but there is no evidence of its existence to the south in this 
quarry. Further evidence of the existence of this channel is found near 
the mill. In constructing the foundation for the large brick stack, one- 
half was built on gypsum rock, and the north half on clay with no trace 
of rock. Drillings made to the south of the quarry and on the hill to 
the east of the mill show a good gypsum ledge. To the north of the 
quarry and west of the mill, borings fail to find gypsum. To the north- 
east across Plaster creek is the Godfrey quarry, where the gypsum is 


found in good thickness. Another possible course of this underground 
channel is suggested from the experience in the old quarry. 

It is said that the lower edge of gypsum disappeared to the west in 
the working of the old quarry near the Grandville road in 1876, and 
caused the abandonment of that quarry and the opening of the new one. 
This old quarry is now filled with water so this account was not verified 
by the writer. Borings on the west side of Plaster creek between the 
two quarries are reported to show no gypsum. Granting the truth of 
these observations, the failure to find gypsum may represent the dis- 
covery of an old water course passing to the northwest from the old to 
the new quarry and then turning to the northeast past the mill. Not 
enough boring records are available to map in detail such a water course, 
or even to prove its existence beyond a possible doubt. 

The upper gypsum ledge, six feet thick, is exposed for several hundred 
feet in the south side of the quarry, but disappears both to the east and 
west within the limits of the quarry. To the west where it has disap- 
peared as a well marked ledge, boulders of gypsum, very much water 
worn, are scattered through the clay shales. On the west and north 
sides of the quarry, no trace of the upper ledge is seen, though it again 
appears in the Godfrey quarry, less than a mile to the northeast, and it 
is found in the workings north of the river. The gypsum in this area 
south of the river shows in this marked degree the effects of past solution 
through water action, so that the quarry men follow the rule that "gyp- 
sum is only found where you find it." 

Tbe work in the quarry at the present time is at the western and north- 
western ends. The overlying shale was formerly burned into brick in the 
company's brick plant located to the east of the gypsum mill. This made 
a very good quality of red brick, some of which was used in the construc- 
tion of the new mill. As the quarry was worked farther and farther west, 
the hauling of the clay became more expensive; and as the new Portland 
cement mill at Newaygo found this clay and shale especially adapted to 
their work, they made arrangements to obtain it and ship the clay to 
their plant, 30 miles north on the Pere Marquette railroad. 

This shale is plowed and then taken in wheel scrapers to the switch 
and dumped into railroad cars through a chute opening in a bridge over 
the track. The gypsum rock is drilled vertically and blasted with dyna- 
mite. The larger blocks thrown out by the blast are broken with sledges 
and loaded into self dumping mine cars. These cars are hauled to the 
end of the 320 foot incline by horse or mule, and there attached to a cable 
which hauls the cars to the top near the mill where they are dumped. 
The rock is hauled from under the incline track on one horse dump carts 
a short distance into the mill. A large quantity of rock is piled up at 
the end of the incline to be used in bad weather and through the winter. 

102 GYPSUM. 

In the earlier history of the quarry, the eleven foot ledge was sorted for 
different uses, and the parts of the layer were so classified. The upper 
three feet of the stratum were used for calcined plaster and was called 
the plaster rock. The next six feet, supposed to be purer in composition 
and so better adapted to the manufacture of finer plasters and especially 
for the manufacture of Alabastine wall finish, was called the Alabastine 
plaster rock; and the lower two or three feet of red gypsum, considered 
as impure, was used for land plaster, and called the land plaster rock, as 
indicated in Figure 11 b. 

At the present time these different parts are all used for the same pur- 
pose and there is no sorting of the rock for ordinary uses. Some of the 
whiter and more compact blocks are separated and hauled in wagons to 
the covered store sheds to the southeast of the mill, to dry or season as it 
is termed, and are then used for the manufacture of Alabastine finish'. 

The quarry rock is mainly compact, without the saccharoidal or sugary 
texture, but has dark seams here and there branching irregularly. The 
seams are caused by dark clay particles and are small in proportion to 
the white gypsum and do not giye a high clay percentage in an average 
analysis of the rock. The crushed rock is snow white and makes a fine 
white plaster. 

Analysis fails to disclose the cause of the color of the red gypsum as it 
is as pure as the white rock and shows no higher iron percentage, and 
when crushed the powder is snow white. 

So far there has been but little trouble with water. The small springs 
in the mines are readily drained away. The level of the floor of the 
quarry is about 10 feet above the water in the river three-quarters of a 
mile to the north. The top of the gypsum is approximately level and 
gives no clue to the dip. As compared with the levels of the Godfrey 
quarry, the gypsum dips 16 feet to the mile toward the northeast. 

The Alabastine Mill. 

The mill of the Alabastine company consists of a central brick struc- 
ture two and three stories high (PI. VI.) 215 feet long and 55 feet wide 
with two frame wings 105 and 75 feet long to the east and west. The mill 
is located about 450 feet north of the quarry. The brick building is used 
for the grinding and calcining machinery. The frame to the west is the 
land plaster department, and the west portion of the brick building is 
the mixing room for the hard plaster (Plasticon). The long frame build- 
ing to the east is the plaster of Paris department and the ware room. 

The engine and boiler house is constructed of brick and located to the 
south of the center of the main building, and thus removes in part the 
danger of fire. It is equipped with two 100 H. P. boilers and a 150 H. P. 
engine. The store room, office, and rock storage shed, are located to the 


south of the mill. The buildings on the left of Plate VI, belong to the old 
plant and the quarry is off to the left of the picture. Plaster creek is 
back of the mill. 

At the center of the large building on the ground floor are located two 
Butterworth and Lowe jaw crushers right and left of the entrance, with 
the crackers just below them. North of the crushers in the same room are 
four runs of four foot buhr stones for. grinding the rock for cal- 
cined plaster, and one vertical emery stone mill with a capacity equal o 
two runs of stone used for grinding land plaster. 

The coarsely ground rock is carried by elevators from the crackers to 
storage bins on the second floor, from which it passes by spouts into the 
hoppers above the buhrs and the emery mill. The flour-gypsum is carried 
from the stones by screw conveyors to the east room and elevated to bins 
above the kettles. 

The kettle room, also built of brick, is three stories high w T ith the 
storage bins on the third floor and the kettles extending from the first 
floor up into the second. The bins extend down into the second story 
with a long V shaped base which opens into a wooden trough or spout 
carrying the gypsum into the kettles. There are four ten-foot kettles, 
each of which will hold nearJy ten tons of gypsum. Two of these kettles 
are connected with the large brick stack and two are connected with 
separate vapor stacks through which the water passes off. The fuel is 
added below the kettle on the first floor, and the finished plaster is 
dumped into fire proof bins on this floor. After cooling 'for a short time 
the plaster is taken by long screw conveyor to an elevator at the end 
which carries the plaster above and over by another conveyor to the west 
end of the brick building to another set of storage bins. From there it 
passes down into the mixing rooms where it goes into the Broughton 
mixers in which a certain amount of retarder is added to form the 
Plasticon wall plaster, or the plaster is carried to the east ware room 
and sacked without retarder as plaster of Paris. The plant has a capacity 
of 135 tons in ten hours. 

The Alabastine mixing plant is located on the Grandville road on the 
bank of Plaster creek and is the original Granger & Ball gypsum mill 
remodelled and enlarged. It is a two to four story frame building 400 
feet long and 200 feet wide, with two frame warehouses 40 by 100 feet 
attached on the north side. On the ground floor are located the power 
plant, the packing machinery, and the secret machinery designed for the 
manufacture of this wall finish. One room is used for the manufacture 
of paper boxes and another for wrapping and packing. On the second 
floor are eight runs of 30-inch buhrs for regrinding the product prepared 
from material received from the other mill. On the third floor are the 
color mixing appliances designed by the company. 



Alabastine finish is plaster of Paris treated to give its proper working 
qualities and mixed with dry colors. The mixture is reground to the 
finest powder in the buhrs and packed in barrels and other bulk packages, 
or in five pound boxes. The capacity of the mixing plant is about ten tons 
a day and the product is sent to all parts of the country. 

The Godfrey Mine and Mill. 

The Godfrey mine is located nearly a mile to the east of north of the 
Alabastine mine and was opened in 1SG0 and worked until about 1898. 
The workings are now filled with water up to the level of the top of the 
upper ledge. The bank above the gypsum shows some variations from 
the section given for the Alabastine mine. There is practically no gravel 
covering, but the top as exposed shows (Fig. 12) three feet of shale and 
then half a foot of limestone separated from a thin eight inch layer of 



\ 1 

40" JpT^E 1 Shale. 










Pws. 12. Section of the 
Godfrey quarry. 

EI Hmtd Sk«le 

Fig. 13. Section at Tay- 
lor brick yard. 

gypsum by 30 inches of shale. Below the gypsum come 4(5 inches of 
shale, the lower six inches showing an incrustation of alum. This shale 
rests on another three inch ledge of limestone followed by 32 inches of 
black shale and a foot of red streaked gypsum and a four inch ledge of 
limestone. Forty-six inches of shale separate this limestone from the six 
foot stratum of gypsum at the water level. 

A short distance east of this quarry, a section of the Taylor brick yard 
shows similar conditions to the Alabastine mine with the absence of the 
six foot gypsum ledge. Here are found in a boring seven feet of gravel 
and 31 feet of shale and clay used for the manufacture of brick, resting 
on an 11 foot stratum of gypsum. Following the record down below this 
gypsum, there are 12 feet of shale and 18 inches of hard rock, probably 
limestone, and then 20 feet of gypsum. 

Geological Survey of Michigan. 

Vol. IX Part II Plate XIII. 




The old work at the Godfrey mine was on the 11 foot ledge which has 
been removed over a large area extending from the wagon road at the 
east to the railroad switch to the mill at the west. The rock as far as 
we can judge from the fragments scattered around the quarry and from 
the account of the former foreman, Mr. A. J. Wright, was of the same 
general character as at the Alabastine mill. 

A large portion of the old mill is still standing to the northwest of 
the quarry. It was a two and one-half story frame building equipped 
with a Godfrey double nipper and cracker for crushing the rock, and with 
two vertical disintegrators made by Butterworth and Lowe, for the fine 









72 oof 



CxVv Y??A 






O Q _, 



£Ul S^IaU 

'■■' i/tsu 



Fig. 14. Section at Powers' Fig. 15. Section Grand 


Rapids Plaster Co. mine. 

Fig. 16. Section Durr Mine. 

crushing and a single run of buhr stones. The mill was run by water 
power from Plaster creek. A separate building contained two ten foot 
kettles and the storage bins, but this was destroyed by lire a couple of 
years ago. A large roofed storage shed was built just south of the 
quarry and the rock was hauled in dump carts to the mill. The property 
is now idle and is owned by the Godfrey estate. 

Powers Mine and Mill. 

This property is located within the city on the west bank of the Grand 
river about midway between the Pearl and Fulton street bridges. Mr. 
Wm. T. Powers organized the company and sunk the shaft in 1890. The 



mine goes 50 feet below the bed of the river and the framework of the 
shaft is built up 35 feet more to the floor of the mill. The record of the 
shaft has been lost and the section represented in Figure 14, is given from 
the memory of Mr. Powers of the boring made to the roof gypsum and 
60 feet below it. The company owns 30 acres of this gypsum land. The 
upper ledge six to eight feet thick is left for a roof and the mine is 
worked on a room and pillar system with rooms about 50 feet square and 
the pillars 20 feet. 

It is estimated that by this system about three-fourths of the gypsum 
can be removed. 

The mill was built on the bank above in 1898, and was burned in the 

Fig. 17. Day's Light niog Plaster Mixer. 

spring of 1903, and the company is known as the Gypsum Products Co. 
The frame mill was built in an L shape, 130 feet long east and west, and 
25 to 50 feet wide with a storage shed built to the east 20 by 20 feet. The 
wareroom to the west was two stories high and the wider portion was 
three stories. On the second floor were placed the nipper and cracker and 
the buhrs below them in two sets, one of 30-inch for ordinary grinding, 
and a pair of 30-inch buhrs for regrinding. A part of the flour gypsum 
was carried by conveyors to the west part of the room and sacked for land 
plaster, and part was elevated to the third story over the kettle placed in 
the north part of the L extension. The gypsum then passed into the 
Powers patent kettle which was ten feet in diameter with a new design of 
flues described in the chapter on Technology, and it was heated by a wood 
fire. The finished plaster was dumped into fire brick bins and elevated to 
bins over the Broughton mixer where it was mixed with retarder to form 
wall plaster. 


A special feature of the manufacture at this mill was the granite wall 
plaster, a sanded mixture ready to be mixed with water and applied to 
the wall. For this purpose there was on the basement floor a revolving 
cylinder sand dryer heated with wood fuel. The dried sand and retarder 
were mixed with the plaster of Paris in a Day's Lightning Plaster Mixer, 
as shown in Figure 17. 

Grand Rapids Plaster Company Mines and Mills. (Plates X, XI, XV.) 

On the north side of the river the gypsum is obtained from under the 
hill by an inclined hillside double entry tunnel. The Grand Rapids 
Plaster Co. have two double entry mines, one at each of their Eagle 
mills, known as mine No. 1 and mine No. 2. The main entry runs north 
and starts into the hill about the top of the 12 foot ledge. The section 
of the hill for 26 feet above the entry is given in Figure 15, a section 
which extends from the fence down, in Plate XV. About three feet of 
gravel are underlaid by 12 feet of shale separated at the center by eight 
inches of shaly limestone. Below the shale is a ten inch layer of gypsum 
seen in the photograph above the entry, and separated by three feet of 
shale from the six to seven foot upper ledge of gypsum. One foot of shale 
divides the upper from the 12 foot gypsum rock. The hill extends above 
to the wagon road 40 to 45 feet above the entry, and north of the road 
the hill rises 100 feet higher though not show T n in the photograph. 

The seven foot ledge is left for a roof and the 12 foot ledge is quarried 
for plaster rock. This is worked by a room and pillar system with rooms 
about 40 feet square and is mined by drilling holes in the upper half of 
the face of the rock and blasting down with dynamite. This leaves a 
bench or ledge six feet high which is then drilled vertically and blasted ; 
all of the mining is carried on by this drift and bench system without 
any undercutting. Pillars of gypsum are left to support the roof, 15 to 
20 feet in diameter and between the pillars intermediate timber posts 
are placed making the mines or caves as they are locally called, perfectly 
safe. No accidents from caving roof have ever occurred in mine No. 1. 
In No. 2 there has been no caving of the roof since 1881. At that time 
the roof covering about five acres fell in one night. The cause was in the 
placing the pillars too far apart, and the lack of sufficient intermediate 
posts. Since that time water has been somew T hat troublesome in this 
mine, and about 150,000 gallons are pumped out in a week. 

Mine No. 2 is similar to mine No. 1, and now the two are connected, 
and in all about 45 acres have been worked out. The character of the 
gypsum is about the same as in the quarries south of the river, showing 
a compact rock cut by numerous dark seams and with the red rock and 
the pencil rock at the bottom. 

108 GYPSUM. 

The Eagle mill No. 1 is a short distance south of the mine entry and 
consists of a group of frame and brick buildings connected by overhead 
enclosed bridges which are for the conveying of material from one depart- 
ment to the other. 

The rock is hauled in mine cars by cables up an incline track to the 
second floor of the frame machinery building and is crushed in a nipper 
and cracker, the rock is further crushed to flour in the four runs of buhrs 
on the same floor as the nipper. The fine gypsum is then elevated to the 
third floor where the material for land plaster is carried through the 
overhead bridge to the west to the land plaster warehouse. The material 
for calcined plaster is carried to the east through another overhead bridge 
into storage bins in the two story brick calcining building. There "are 
three ten-foot Powers kettles, which are connected with the high brick 
stack. The calcined plaster is carried to the east room into the large 
ware room 225 by 40 feet with a bulk capacity of 5,000 barrels, and 
sacked or placed in barrels as wanted. The engine and boiler house built 
of brick one story high is at the side of the machinery building. The land 
plaster warehouse is a one and half story frame to the west. 

This mill and the No. 2 mill are located on the L. S. & M. S. R. R. track 
about two and one-half miles west of the city of Grand Rapids. The 
Eagle mill No. 2 is located a short distance west of mill No. 1 and is 
equipped with a Godfrey double nipper and Lowe cracker and the fine 
grinding is done in three runs of vertical emery stone mills and the re- 
grinding of very fine plaster in two runs of 80-inch buhrs. There are 
three ten-foot kettles arranged similar to the plan of the No. 1 mill. 

The English Mill and Mine. 

The English mill of the United States Gypsum Co. is located to the 
west of the mills last described. It is a three story frame building 40 by 
50 feet with a mixing and grinding room to the east 60 by 40 feet. The 
rock is brought in mine cars from the shaft down a slight incline to the 
second floor of the mill where the nipper and cracker are located. The 
broken rock is then elevated to bins above the two runs of buhrs, and one 
vertical emery stone mill, where the rock is ground to flour which is 
carried by a screw conveyor and elevated to the third floor above the two 
ten-foot kettles. The mill is also equipped with three sets of regrinding 
buhrs for the finer plaster. 

The hot calcined plaster is dumped into lire proof bins and then ele- 
vated and carried by conveyors to the ware room at the east where it is 
sacked for the market. This mill was erected in 1900 and has a daily 
capacity of 150 tons. 

The gypsum rock is obtained from under the same hill that is worked 


to the east by the Grand Rapids Plaster Co., but it is reached by a vertical 
shaft on the hillside, 62 feet deep. The shaft is six by eight feet in sec- 
tion, containing double elevators and an independent air shaft. The 
elevators work alternately and are operated by electricity. The cars 
carry 2,500 pounds. The drilling in the mines is done by electric drills 
and the mine is lighted by electricity. The area now worked out is about 
three acres. This is one of the best equipped mines of gypsum in the 

The first rock worked in this shaft is a 12-foot ledge, and the six-foot 
upper ledge is left for the roof. The characters of the rock are similar 
to those in the other mines of the Grand Rapids area. 

§ 2. Grandville Area. 

The gypsum quarries of the Grandville area are three-fourths of a mile 
south of the town. The location is four miles west and five miles south 
of Grand Rapids, or seven miles by the Pere Marquette railroad. The 
mines are located in the northwest quarter of section 20 and in the north- 
east quarter of section 19 in Wyoming township. The old Red mill is 
located in the corner of section 19 and it is now filled with water and has 
been abandoned for 20 years. 

Across the road in section 20 is the quarry of the White mill, now idle, 
and to the north in the next field is the quarry of the Durr mill. Both 
of these quarries have large areas w r orked out. They are worked by strip- 
ping off the surface covering of gravel and so are open quarries. 

A section of the Durr mine is given in Figure 10, and shows 20 feet of 
gravel and one foot of blue shale over the 11-foot ledge of gypsum which 
rests on a four foot layer of hard shale which forms the b6ttom of the 
quarry. Borings show a 14-foot gypsum ledge below this. The lower 
ledge is not worked as water is a source of trouble at the present level of 
the quarry and must be kept down by pumps. 

The upper gypsum ledge at the Grand Rapids quarries appears to be 
absent in these quarries, and the upper surface of the 11-foot ledge is very 
uneven and shows in a marked degree the effects of solution. The gravel 
cover coming down almost to the gypsum is in marked contrast to the 
Grand Rapids quarries. The lower part of the 11-foot ledge is of red 
color and the cone in cone layer reaches six inches in length and is in 
places free from the red color. 

The origin of such cone in cone structure in clay materials has been 
much discussed, but never satisfactorily explained. Dana regarded such 
a structure in clay shales as due to the concretions formed under pres- 
sure. I have found in western gypsum quarries a layer of satin spar 
needles on the under surface of the gypsum ledge in the same position as 
these cones, and the fibres standing vertical as they do in these cones. 

110 GYPSUM. 

The origin of the satin spar in the Kansas gypsum seemed to be due to 
gypsum waters percolating downward and depositing gypsum in needles 
which are thus secondary in origin. It is possible that the preceding sug- 
gestion of Dana in the cone in cone structure in clay may explain the 
origin of this gypsum structure; that pressure acting at the same time 
as the formation of the secondary spar, might cause a consolidation of 
the needles and form the cone in cone structure as seen in the Michigan 
quarries. The Michigan gypsum is more compact than the Kansas de- 
posits and so appears to be more firmly consolidated. 

The gypsum rock is taken from the Durr quarries in cars and hauled 
by horses or mules along a T-rail track a little over one-half mile north- 
west to the mill. A shaft has been excavated near the mill, down through 
the 32-feet of gravel to the gypsuin. This proved a troublesome operation 
on account of the caving of the gravel, but the shaft has now been firmly 
timbered, and the mine will be opened and equipped with electricity, and 
made equal to the English mine at Grand Rapids. When this is com- 
pleted the quarry will be abandoned. 

The Durr Mill, (Plate XIIA.) 

The rock from the quarry is stored in two long sheds and hauled from 
these into the mill on the ground floor where it passes through the nipper 
and cracker and is hoisted by chain elevators to the second floor. It 
here passes through four four-foot buhr stones and the rock flour is con- 
veyed and elevated to the bins above the kettles which are three in num- 
ber, two of these are eight feet in diameter and one is ten feet. 

The crushing and calcining machinery are in the three story building 
at the south end of the long mill. This portion of the mill is connected 
with the three story mixing plant at the north end, by a ware room, giving 
a storage capacity of 900 tons. 

The calcined plaster is elevated from the bins below the kettles and 
carried by a long overhead screw conveyor through the ware room to the 
mixing plant. The plaster of Paris is taken out at various points in the 
ware room where it is sacked. In the mixing plant the plaster of Paris 
and retarder are mixed in Broughton mixers. 

A special feature of the work at this plant is the manufacture of 
Adamant wall plaster. The sand for this mixture is dried in three 
Perfect sand dryers built like a large stove with hopper on the top into 
which the sand is shoveled and coal is fed in below. The capacity is ten 
yards a day for each dryer. A cylindrical rotary sand dryer has been in- 
stalled to take the place of these stoves, and it has a capacity of 60 tons 
a day. 

The dried sand, plaster of Paris, and retarder, are mixed in one of the 
two Broughton mixers and then sacked in 13Q, to 140 pound sacks, while 


the ordinary plaster, also made in this mill is placed in 100 pound sacks. 
The patents for Adamant plaster are owned by the United States Gypsum 
Co., and it is made at a number of their plants. 

White MM (Plate XIV.) 

The White mill, named from the color of the building, is located near 
the Durr mill quarry and has now been idle for four years. It is owned 
by Mr. Dummer of Chicago. The mill though idle is kept in good con- 
dition and is under the care of a watchman day and night. 

In the center of the building is the power plant with a 150 H. P. Allis 
engine, steam pump, and small compound engine. The room just south 
contains the two boilers, and south of the boiler room is the kettle room 
with four ten-foot kettles with fire brick bins below. The fuel for the 
kettles and the boilers is added at the east end of this room, and the 
kettles are so arranged that they can be readily reached and repaired 
from any side. 

The rock was brought from the quarry in large boxes carried on an 
overhead cable operated by a large drum and engine in the upper part of 
the building. The cable was supported by two towers, one near the mill 
and the other on the opposite side of the quarry. The gypsum was 
dumped in a room to the north of the engine room and was thrown into 
a Lowe nipper and cracker; then hoisted by an elevator to a half floor 
above where it passed though four runs of 36-inch buhr stones. The 
gypsum flour was elevated and carried to the south to bins over the 

The calcined plaster was elevated from the fire proof bins and carried 
by a screw conveyor to the north of the engine and crushing rooms into 
the sacking and storage room. This long room is divided into a series of 
smaller rooms or bins, and from these the sacks or barrels were loaded 
on the cars on the switch built on the west side of the building. 

The Red mill (Plate XIII.) across the wagon road from the White mill 
is one of the oldest mills standing. It was dismantled a number of years 
ago and is now passing into rapid decay. 

§ 3. Alabaster. 

The Alabaster mine and mill are located six miles south of Tawas City 
and three-fourths of a mile back from Saginaw Bay. and the bottom of 
the quarry is about 15 feet above the water in the bay. The quarry is 
located in the northwest corner of section 27 of Alabaster township in 
Iosco county. A large area has been worked out during the past years of 
its history, and over a half mile of face is now exposed. Probably no 
gypsum quarry in the United States turns out as much rock in a year 
as this one which has an annual output of a hundred thousand tons. The 

112 GYPSUM. 

workings show a solid ledge of gypsum 18 to 22 feet in depth covered 
toward the bay by five to eight feet of clay with gravel through it, and 
toward the west by 12 to 16 feet of stiff boulder clay which is stripped by 
means of a steam shovel with a capacity of 840 cubic yards a day. The 
clay is loaded into small dirt cars and hauled by a small steam engine 
and dumped into the abandoned parts of the quarry. 

The rock is drilled to a depth of 16 feet and blasted with dynamite, and 
the larger masses from the blast are broken with sledges and loaded into 
small ballast cars and hauled by a second steam engine to the mill or to 
the wharf. 

The rock is compact and more or less streaked or banded with darker 
streaks composed of clay and dark gypsum. Selected masses are snow; 
white without a trace of dark color. The lower one and one-half feet of 
the ledge are red in color and near the bottom are composed of nodules of 
reddish or white gypsum surrounded by impure clay gypsum. On weather- 
ing the nodules separate and the dark portion crumbles. This portion of 
the ledge is thrown to one side and is not used at the mill. The floor of 
the gypsum is a fine grained, bluish sandstone. 

It is stated that an old shaft was put down in the quarry 65 feet below 
the level of the basal rock and passed through a total of 25 feet of gyp- 
sum. According to Mr. Gregory, in the earlier history of this quarry, 
there were two layers of this gypsum separated by a layer of hard fos- 
siliferous limestone and a small stratum of shale, but upon working into 
the deposit the shale and limestone have entirely disappeared. The 
mine and mill are connected by a five mile switch with the Detroit and 
Mackinac R. R. 

The mill is built about half way between the quarry and the bay. This 
consists of a group of buildings, the main one being 40 by 52 feet and con- 
tains the grinding machinery and the three ten-foot kettles built with the 
four interior flues on a line. An extension has been made to the machinery 
building which is 24 by 64 feet and reaches out to the railroad track. The 
upper part of this building is the storage room for the bulk plaster and 
this is sacked below and loaded directly on the cars. 

A shed 200 by 28 feet has been erected to store sacks and the finished 
product, with an extension 40 by 100 feet which adds 1,500 tons storage 
capacity. The rock shed is 40 by 200 feet and will hold 3,500 tons of 
rock stored for winter use. The two story carpenter shop was used at the 
old mill for the manufacture of barrels and nearly 30,000 of these were 
used every year, no material being sent out in sacks. In the new mill, 
built in 1892, sacks have been used, and only about 7,000 barrels are 
needed a year. These are made in the carpenter shop which is also used 
to store parts of machinery, lumber, and the like. 

In addition to the mill buildings, the company has erected 40 houses to 

Geological Survey of Michigan. 

Vol. IX Part II Plate XI V. 



accommodate the workmen, a two story hotel 70 by 80 feet, and an office 
building and store 60 by 60 feet. The rock which is shipped by water is 
hauled in cars by the small engine out on the 600 foot pier and loaded 
directly into sailing vessels holding 450 to 700 tons, or it is stored in a 
two story warehouse 40 by 100 feet, built on the end of the pier. The rock 
is hauled up an incline to the second story and loaded through iron chutes. 
The finished product is hauled into the lower part of the warehouse and 
loaded by hand trucks on the boats. 

In the Alabaster mill grinding machinery is on the first floor and con- 
sists of a Lowe nipper not used at the present time, and a large cracker 
into which the rock is now thrown as it comes from the quarry. The gyp- 
sum is then ground in a Stedman disintegrator or in three runs of buhr 
stones. Two sets of 36-inch buhrs are used for regrinding the rock flour 
for superfine plaster used especially in the plate glass works. The mill is 
equipped with one Raymond machine, formerly used for grinding this 
extra fine plaster, but it has been out of use for some time. The gypsum 
flour is elevated in double bucket elevators and carried in screw conveyors 
to bins over the kettles. The calcined plaster is elevated and conveyed to 
the store houses by long conveyors one of which is 150 feet long. In the 
ordinary plaster the retarder is added in two Broughton mixers. Power 
is furnished by a 150 H. P. engine and the capacity of the mill is 200 
tons in 24 hours. 

Other Qypsum Deposits in the Alabaster District. 

West of Alabaster Point, according to Winchell, 1 the gypsum formation 
can be found for a distance of 30 miles near the surface on all the head 
branches of the Au Gres river. 

"In township 21, range 5, section 12, is another similar exposure of rich 
gypsum deposits, and numerous smaller deposits are noticed in the beds 
of creeks between that locality and the lake." 

Prof. W. M. Gregory* has made a very careful study of the geology of 
this region, and his account of the distribution of the gypsum is given in 
§ 6 of Chapter V. 

"The outcrops of this formation have a limited area in this region and 
no evidence of gypsum in the Grand Rapids group outcropping has been 
found north of the line connecting Tawas City and West Branch and 
south of a line connecting West Branch and Au Gres. Gypsum is found 
in the deep wells of the Saginaw valley, but the above statement refers 

lGeoL Survey of Mich., Vol. III. p. 107; 1870. 

•GeoL Surrey of Mich., Annual report for 1901, pp. 16-18. 


114 GYPSUM. 

to a region in which a search might reveal the rock in suitable condition 
for practical working. 

Judge Sharp, of West Branch, is the authority for the statement that 
three and one-half miles east of West Branch on the Rifle river is an out- 
crop of gypsum, which several years ago caused much excitement for its 
size and purity. No careful exploration of this bed has been made and at 
present it is undeveloped." 



§ 1. General Process of Manufacture. 

Gypsum rock as described in the chapter of Chemistry is a mineral 
composed of sulphate of lime and water (CaS0 4 , 2H 2 0). When this rock 
is heated to the proper temperature it loses part of the water and is then 

FiG. 18. Jaw Crusher for Crushing Gypsum. 

known as planter of Paris (CaS0 4 ) 2 . H 2 0, a compound cjipable of taking 
up water when it is added to it, forming the set plaster. 

Thd essential parts of the process of manufacture are the proper grind- 
ing and proper burning, and it is the aim of this chapter to present the 
methods used in reaching these results. 

In a number of the foreign countries, especially in France and in some 



of the English mills described in an earlier chapter, the gypsum rock is 
burned and then reduced to powder. The practice in the Michigan mills 
and practically all the mills of this country, is to crush the rock and burn 
the rock flour in kettles or cylinders. 

Most of the material in the United States is prepared in mills and 
kettles of the same general type ; but there are some variations regarded 
by many of the plaster men as improvements, and there have been some 
attempts at improvement which have proved to be failures. 

§ 2. Crushing of the Rock. 

In the typical Michigan mill the gypsum is treated according to the 
following plan : On the second floor of the mill are placed the jaw crusher, 
the nipper and the cracker. The nipper as shown in Figure 18 has a cor- 
rugated face plate of chilled iron forming the end of the machine, and 
a swinging apron of the same pattern which forms a V shaped box. The 

Fio. 18. Gypsum Disintegrator, made at Aurora, Indiana (olosed). 

apron is driven against the fixed plate by an arm which moves with an 
eccentric motion on the shaft, so as to give a backward and forward move- 
ment, and the shaft is moved by steam or water power. Such a machine 
weighs about 6,000 pounds and has a capacity of seven to eleven tons per 
hour. Mr. Godfrey invented a double swinging apron jaw crusher which 
gave an increased capacity, but it is only used in two mills in the State. 
Blocks of about 50 pounds weight are thrown into the jaws of these 
machines and are crushed into pieces about the size of a man's hand. The 
small masses drop from the crusher into the cracker set in the floor ju*t 
under the crusher. This machine has a conical corrugated shell in which 
revolves a shaft with a corrugated iron shoe, working like a coffee mill. 


Three sizes of this type of machine are made, with a capacity of three, 
seven, and twelve tons per hour, the usual size is the medium one which 
has a weight of 3,300 pounds. The cracker was originally patterned after 
the old corn mills which ground the cob and corn in one mass. 

The gypsum is further crushed in the cracker into fragments of the size 
of small gravel, which fall into the buckets of a chain elevator whereby 
they are raised to storage bins on the floor above. From this bin the gyp- 
sum particles pass down by gravity through spouts into ordinary buhr 
mills or emery stone mills, where they are ground into flour. 

Pig. 20. Gypsum Disintegrator, same as Fig. 19 (open). 

The two buhr stones are arranged as in a flour mill usually with upper 
runners, and ranging in diameter from 32 to 42 inches. Most of the buhrs 
in Michigan are French stones obtained from old flour mills. They are 
cut in radiating furrows and when ground smooth by the friction of the 
gypsum particles must be redressed. This operation requires skilled labor 
and usually one man is employed at the mill for this purpose. It is also 
necessary to have an extra set of buhr stones as in a large mill one set is 
out of use most of the time. 

To increase the capacity and avoid the expense of dressing the buhr 
stones, other types of machines have been invented, and used to some ex- 
tent in the Michigan mills. One of these is the lime disintegrator, in- 

118 GYPSUM. 

vented and made by the Stedman Foundry and Machine Works of Aurora, 
Ind. One of these disintegrators is used in the Alabaster mill and in the 
Chicago mill of the U. S. Gypsum Co. This machine as shown in Figures 
19 and 20, consists of two cages with short cross bars. These cages travel 
at high speed in opposite directions. In the Alabaster mill, the disin- 
tegrator runs at a speed of 800 revolutions per minute. The gypsum is 
carried by a spout into a hopper at the side and passes to the center of 
the cages where the centrifugal force carries the particles between the 
bars of the cage. These bars passing in opposite directions beat the rock 
into powder by the impact against the bars, and by the striking of the 
gypsum particles against each other. . There is no danger of choking or 
clogging of the machine and the action is rapid. The capacity of a 50-inch 
disintegrator is 60 to 75 tons in ten hours. 

Another type of machine for crushing the gypsum gravel from the 
-cracker to flour is the Sturdeyant emery-stone mill, made by the Sturde- 

J- -Ml 

% i \j '• 


Fig. 81. S turd ev ant Emery Mill. 

vant Co., of Boston. This mill, as shown in Figure 21, is made after the 
pattern of buhr stones set to run in a vertical direction. Its grinding 
surface is composed of large blocks of emery stone as it comes from the 
mine, set in a metal frame. These blocks are so arranged that the grain of 
the emery runs at right angles to the face of the stone, giving the maxi- 
mum cutting power. It is made of large pieces fitted as closely as possible 
and the crevices filled in with smaller emery. A special composition 
metal is then poured in from the back making a solid casting, and the 
whole is strengthened by steel bands. The center of the mill stone (Fig- 
ure 22) is made of buhr stone in order to produce a more even wear on 
the surface, as the speed and consequent wear is greater toward the 
border than near the center. The bed stone is bolted to the mill frame 
and does not have to be removed till the stone wears out. 
These emery mills are said to reduce the cost of grinding nearly one- 


half, and can be dressed in much shorter time than ordinary mill stones, 
and they can be run at much higher speed. Such mills are made in sizes 
from 30 to 54 inches in diameter. The 30 inch emery stone mill weighs 
3,500 pounds and will grind one to four tons per hour, requiring from 18 
to 20 H. P. 

Fig. 22. Sturdevant Emery Mill Stone. 

§ 3. Calcining. 

After the gypsum is ground to flour by some of the methods described 
above, it passes into a screw conveyor, and is elevated directly to the 
floor above and then conveyed into storage bins located over the kettles. 

The ground gypsum flour is allowed to run by gravity from the storage 
bin into the calcining kettles. All of the kettles in Michigan are con- 

Fig 23. Day Fiber Picker. 

structed after the same general plan, a plan introduced from New York 
by Mr. Godfrey. The kettles are constructed in the form of a hollow 
cylinder made of boiler steel three-eighths of an inch thick and are about 
as deep as wide, ranging from eight to ten feet, and the latter is the usual 
size in Michigan. The cylinder sets on an iron ring and on this ring in- 
side of the kettle is placed the convex bottom made of such a mixture of 



irons that it will have a low shrinkage, even as low as 3-64 of an inch in 
passing from the molten to the cold stage. This bottom is made convex 
upward and about % of an inch in thickness fitted with small rings at the 
top which enable one to fasten chain and tackle to it and so place the 

8 sii 1 







bottom in the kettle where it is firmly fastened to the cylinder with 
moulder's cement. Sectional kettle bottoms have been invented and are 
made by the Des Moines Mfg. and Supply Co. On account of the uneven 
contraction and expansion in different parts of the kettle resulting in the 
warping or buckling of the plates, it is claimed at the Michigan mills that 



















it is very difficult to fit in the single pieces. This type of kettle bottom is 
used in a number of Iowa and Kansas mills and they are said to be satis- 
factory in those mills. They are made in six radial sections and one 
center piece. A ten foot kettle bottom weighs approximately 4,400 pounds. 
The kettle is set like a boiler upon a brick base and surrounded by a 
wall of brick 121/2 to 17 inches thick separated from the kettle by seven to 
ten inches of air space. The grate bars were formerly placed four feet and 
now seven feet below the kettle bottom. The fire place is about four and 

Fig. 83. Four Flue Gypsum Calcining Ke 

one-half by three feet, though in one Michigan mill the grate is six by four 
feet. It requires about 3,300 fire brick and 19,000 common brick to set 
such a kettle. Figure 24 shows the plan of a four-flue kettle set in position. 

Figure 25 shows the general plan of a plaster mill with kettles, ele- 
vators, storage bins, etc. 

In the old style of kettles no flues passed through the kettle, but in the 
kettles now in use, there are two to four flues passing through the kettle 
about the center. In the Michigan kettle four flues are used, two above 
the center and two below, as shown in Figure 26. In the Butterworth & 


Lowe kettle there is a diyision between the two sets so that the heat passes 
up in the open space on one side and through the lower two flues, then 
back through the other set and out through the chimney flue. In the 
Iowa type of kettle and in a few of the Michigan kettles the four flues are 
on a line. The kettle flues have been gradually increased in diameter 
from 7 inches to 16, and are 36% inches apart on the horizontal line in 
a ten-foot kettle, and are ten inches apart up and down. 

The experiment tried on the amount of fuel required to calcine plaster 
in two kettles, one with the four flues on a horizontal line, and one with 
the flues arranged two above and two below, appears to show an advantage 
in favor of the latter arrangement. The results of this experiment are 
given in the following table kindly furnished by Mr. Lowe of Grand 

The kettles were properly set and with good draft. The gypsum was 
ground so that 85 per cent would pass through a 40 mesh sieve. The ex- 
periment was watched on the second batch after the kettle had been fully 
heated. The material was discharged after the second settling and was 
fully calcined, and the weight of plaster was eight and one-fourth tons, 
with a water percentage of five and one-half. 

Type of four-flue kettle. 

Direct, flues 0000. . 
Return, flues -^- 

Direct, flues 0000 . 

00 ' 

Return, flues 

of rock. 

Green . 


Pounds of 
bitum. coaL 



in bours. 

8 7-12 
3 8-12 
2 10-12 
2 11-12 

H. P. 



The material in the second experiment was discharged at the end of the 
first settling and total weight of plaster was eight and one-half tons, with 
a water percentage of eight. In the direct arrangement the heat passes 
through flues and out. In the return the heat passes through two flues 
then back through other two and out. 

Type of four-flue kettle. 

Direct, flues 0000. 

« 00 

Return, flues-— - 

Direct, flues 0000. 

Return, flues -„- 

of rock. 

Green . 


Pounds of 
bltum. coal. 

in hours. 


2 9-12 


2 10 12 


2 1-12 


2 2-12 

H. P. 


124 GYPSUM. 

These kettle flues are arranged with openings in the brick work, closed 
by doors which can soon be opened and the flues cleaned from time to 

The gypsum flour is constantly stirred on the bottom of the kettle by a 
convex revolving arm with a length equal to the diameter of the kettle, 
and with small cross pieces projecting below and set at an angle so as to 
reach all portions of the bottom. The arm is fastened to a four inch 
vertical shaft which is driven by a five foot horizontal cog crown wheel, 
set in motion by a one foot vertical pinion wheel attached to the power 
shaft. Above and below the flues two stirring rods are also attached to 
the vertical shaft. It requires 10 to 25 H. P. to run this stirrer, and some- 
times if the plaster is run too fast into the kettle, the resistance is suffi- 
cient to break the teeth or cogs from the pinion wheel. The stirrer makes 
about 15 revolutions per minute. A ten-foot kettle will calcine three and 
one-fourth tons of ground gypsum per hour, and a two kettle mill with 
the necessary machinery for taking care of the rock will require 85 H. P. 
when emery mills are installed. A complete ten-foot kettle with bottom 
and vapor stacks weighs 19,000 pounds. The kettle is covered with a 
sheet iron cover, with an opening or door which can be shifted so as to 
see the interior. 

In the Powers patent kettle 40 three-inch flues are built around the cir- 
cumference of the inside of the kettle, each forming a segment of an oval. 
This arrangement gives more clear space in the kettle and is claimed to 
make a considerable saving in fuel. In the Powers mill at Grand Rapids, 
ten tons of plaster can be made in a ten- foot kettle in one batch. 

In an hour after the gypsum kettles are filled the temperature reaches 
230° F., and the mass is seen to be boiling vigorously, as the water is driven 
off and out through the vapor stacks above. When the temperature in- 
creases to 270° F. (132° C.) the gypsum settles down solid leaving 16 
inches or more of vacant space at the top. and the steam almost ceases to 
rise. At 280° or 290° F. (138° to 143° C.) the mass comes up again, often 
throwing a part of the material over the top of the kettle. When the 
temperature of 350° to 370° F. is reached, the plaster is readily with- 
drawn through a gate near the bottom controlled by a lever above, into 
a fire brick bin on the ground, and the kettle is then refilled. 

In some mills these temperatures are carefully watched and a dial 
thermometer with long rod, or a thermometer attached to a long stick, 
is thrust through the door at the top of the kettle and the temperature 
read. Gypsum plaster is a good non-conductor of heat, and it clings to 
the cooler thermometer bulb or tube placed in the mass, and so causes the 
instrument to record a lower temperature. 

In most of the Michigan plants the expert calciners who have spent 
years watching the plaster, learn to tell the stages of the burning by the 
appearance of the boiling plaster or by the amount of steam passing out 


through the vapor stacks, and even by the creaking sound of the machinery 
caused by the settling down of the plaster throwing more strain on the 
cogs, and when the strain is relieved by the final boiling of the mass, 
the creaking sound ceases. Some calciners with little experience attempt 
to calcine plaster without a thermometer, and then are apt to work 
by guess, making a plaster of variable quality, but such workers are few 
in the Michigan mills, especially at the present time when competition 
$mong the mills requires the best plaster that can be manufactured. 

In the earlier days of the plaster industry the plaster was withdrawn at 
the end of the first settling, and in recent time this method has been fol- 
lowed to save fuel and increase capacity, but such plasters are of lower 
strength and are often rejected by the plasterers. 

The whole process of calcining, after the kettles are heated to the proper 
temperature, requires two and one-half to three hours, and there is a loss 
in weight of 12 to 14 per cent due to the loss of water. Three kettles are 
burned in a day, requiring about 1,200 pounds of coal in dry rock, and as 
high as a ton of coal in moist rock. Where wood is used it requires one- 
fourth cord of slab wood, costing $ 1.90 a cord, to burn ten tons of plaster. 
The favorite coal used is the Ohio and Indiana block. 

The great objection to the present kettle system of calcining is the great 
amount of heat required to calcine the mass of cold gypsum thrown into 
a kettle with thick bottom, and a considerable amount of heat is wasted 
by radiation from the kettle. This has been lessened by the arrangement 
of flues in the interior of the kettle. Another objection is the large horse 
power required to stir this mass of gypsum and so keep it from over- 
burning on the bottom. The great heat at that place tends to warp and 
4rarn out the kettle bottoms which are heavy and expensive to replace. 

In the early history of the Michigan industry attempts were made to 
avoid these troubles by using rotating cylinders as described in the histori- 
cal chapter. Various forms of cylinders have been invented, but with one 
exception, to be described, these have attracted little attention. Butter- 
worth and Lowe purchased one of these patents and improved it, but have 
now ceased to manufacture them. 

The objection given to the cylinder method of calcining is the difficulty 
of determining when the plaster is properly calcined. The expert calciner 
cannot see plaster boiling in the enclosed cylinder, and all of his tests of 
the appearance of the boiling mass, the rising steam, the creaking ma- 
chinery, have disappeared or are so modified that he can no longer recog- 
nize them. He is at a loss to determine the time to draw the finished 
product. If he depends on a time limit of a certain number of hours or 
parte of an hour, the rock may vary in amount of contained moisture and 
so have to be drawn at different times. This might be determined by the 
thermometer, but this method of determining temperatures does not ap- 
peal to men skilled in kettle methods. These objections have prevented 



the rotating cylinders from being adopted in any of the Michigan mills, 
and the method is generally condemned in this State. 
Plaster machinery has improved very slowly in comparison with ma- 

chinery in other lines of pock product manufacture, and it is hoped that 
new and better methods will be invented and that prejudice alone will not 
stand in the way of their adoption. 

§ 4. Cummer Rotary Calciner. 

A year or more ago the F. D. Cummer Co., of Cleveland, Ohio, invented 


a rotary cylinder for calcining plaster, and has installed these in several 
plants. At the present time this is the only company in this country 
which is meeting with any success in this line of gypsum machinery. 
Prom the experience in the Portland Cement mills, this method would 
seem to be the logical method of calcining such plaster, if it could be 









proved that the plaster could be made of good and uniform quality, and 
this the Cummer Co. claim to be doing, and are willing to guarantee. 

The Lycoming Calcining Co. of Williamsport, Pa., is using the Cummer 
process in a plant of a capacity of 50 tons of plaster in 1 1 hours, using 
slack coal as fuel, and they claim there is a large saving in horse power 



and labor over the kettle method, and that the plaster is of a high strength 
and is satisfactory to the trade. 

The gypsum blocks are crushed in a jaw crusher, A, (Figure 27) and 
by rolls, D, so as to pass through a one inch ring screen, G, and the ma- 
terial is then fed into the rotary calciner, G, from the storage bin, F. 
This cylinder is 27 feet long and four feet in diameter set at an incline and 
slowly revolved, It has a large number of hooded openings, J, (Figure 
28) so arranged that heated air and gases are drawn in from the chamber 
around the cylinder. The material is constantly raised and dropped in 
the cylinder by means of the lifting blades. The heated air traverses the 

_- r»g ft/^r»ff 

Fig 29. Cummer Continuous Calcining Kettle (end elevation) 

cylinder in the opposite direction of the material. In Figure 28, A, is the 
stoker front, C, C, are cleaning doors, K, is the discharge for the calcined 
product, H, H, are holes in the masonry in which the pyrometers for 
measuring the temperature may be placed, M, is the driving pulley, F, is 
the hopper, and G, is a fan for controlling the flow of the gases and heated 

The material delivered from the rotary calciner is steaming and heated 
to from 350° to 400° F. Elevators carry the plaster to the three specially 
constructed brick calcining bins, 30 feet long, six feet wide, and 29 feet 
deep, where the resident heat of the plaster completes the process of 
calcination and the material is cooled in about 36 hours. The cooled 
plaster rock is mechanically discharged into the elevator, M, (Figure 27) 




which carries it into small bins placed over the grinding mills, O. From 
these mills the conveyor delivers the pulverized material to the screen, S. 
The finished product is sacked at T. The end elevation of a Cummer mill 
is shown in Figure 29. 

In the kettle method, the calcined plaster after remaining in the fire 
proof bins a time to cool is taken by conveyors and elevators to an upper 
floor and passed over screens. The screens by means of double eccentrics 
have a shaking motion and are usually about three and one-half by four 
and one-half feet in size covered with wire cloth sieve, and are set at a 
sloping angle. The fine plaster passes through and the coarse particles or 
tailings are conveyed back to the buhrs for regrinding. In the western 
United States plaster mills, the sieves are 30 to 35 meshes to the square 
inch. In Michigan and Ohio they are usually 35 to 45. meshes to the 
square inch, and in New York 40 to 55 mesh sieves are generally used. 

In some plaster mills the plaster is screened by passing into a hori- 
zontal cylindrical reel 40 inches in diameter and 10 feet long, slanting 
downward three-eighths of an inch to the foot, and made of 40 mesh wire 
cloth. The screenings in both of these methods average about one per 
cent of the total. 

The screened plaster is conveyed into bins on the second floor of the 
mixing room where it may be run into sacks of 100 pounds weight or into 
265 pound barrels, and sold for plaster of Paris, or as it is called in Mich- 
igan, stucco. This w r ord stucco is used in the United States in a variety 
of ways. In Kansas it usually refers to plaster made from earthy gypsum 
(gypsite). In other sections, and this is the correct use of the term, it 
refers to a plaster of Paris with glue or some retarder added to it to 
delay the time of setting. 

The retarder was formerly added to the plaster in the kettle a short 
time before drawing the product, but this method produced uneven re- 
sults. It is now added in correct proportion in a mixing machine of the 
type of the Broughton mixer shown in Figure 30. This machine is made 
of iron or steel with a receiving hopper below constructed of w r ood, and 
the machine is adapted for continuous operation. 

While one charge is being sacked, another is being mixed, and the third 
is filling the hopper above, which holds 1,000 to 1,400 pounds. The 
capacity of a five bag machine is 300 to 400 barrels per day of ten hours, 
requiring 8 to 12 H. P., and with a weight of 4,750 pounds. 

The finished plaster some years ago was always placed in barrels with 
a weight of 300 pounds. At the present time some of the material is 
placed in barrels of 265 pounds weight, but most of the plaster is sold in 
sacks of 100 pounds weight. These sacks cost about eight cents each in 
wholesale lots and are charged against the customers who receive a re- 
bate of the amount paid when the sacks are returned. 



§ 5. Progress in Technology of Gypsum Plaster. 

In the early days of the Michigan plaster industry, the calcining was 
done in cauldron kettles holding a few barrels and stirred by hand. A 
little later several of these kettles were set in an arch similar to the plan 
now used in the kettle block system of making salt from brines. This 
crude method was improved by Mr. Freeman Godfrey, by the construc- 
tion of a six foot calcining kettle with a stirring appliance moved by 
water power. These kettles were increased to eight feet and then to ten 
feet in diameter, and one company has even considered a 12 foot kettle. 
Experience seems to show that in economy of fuel and power, the most 
profitable kettle is the ten foot size, and this has now come to be the 
standard size in gypsum mills. 

Fn.\ a». Hrougbton Plaster Mixer. 

The interior tlue system enabled the plaster to be calcined with less 
fuel than without, and in many of the western mills two flues are con- 
sidered as good as four and give greater capacity to the kettle. If no 
partition is added in the air space around the kettle to separate the two 
sets of flues, there seems to be no advantage in the extra two flues. The 
Iowa plan of four flues on a horizontal line seems to require more fuel 
than in the arrangement of two above and two below, as indicated in the 
table given under that section of this chapter. 

The size of the flues has been increased from 5 to 10 inches in 
diameter, and this is regarded as the maximum size for economical work- 
ing of plaster, though there is some difference of opinion on this point. The 
size of the grate has been increased and most plaster men agree that a 
fire place four and one-half by three feet is the most economical. 

Progress, then, in calcining plaster in Michigan in the past 30 years 


has been in enlarging the capacity of the kettle and in the saving of fuel. 
In the early days when wood was abundant and was the only fuel used in 
this work, there was no incentive to improvements which would save fuel. 
In the present day of active competition and occasional cutting of prices, 
it is important to save expense at every turn and to improve the product 
as much as possible. 

The improvement in product has been in the more complete removal of 
water in the gypsum rock. The old plasters were removed at the end of 
the first settling as fully calcined. Such plaster would scarcely sell today 
at any price in competition with plaster removed after the second settling. 

Another improvement has been along the line of fine grinding and in 
crease in capacity of grinding machinery. Some mills today are turning 
out a plaster so finely ground that there is scarcely a trace of grit in the 
mass. The Stedman disintegrator, and the Sturdevant emery mill give 
a greater capacity for the power required and cost less for repairs than 
the old style buhr mill, but many plaster manufacturers claim the re- 
sulting plaster is not so fine in grain. With the use of these machines, 
when a very fine ground plaster is needed for any special kind of work 
it may be reground in a small buhr mill. For ordinary wall plaster work 
it is very doubtful whether such line plasters are any better than the 
coarser grades. 

This progress in improvement in grinding machinery has only come in 
the last few years and is so new to many plaster men that they are nor 
ready to adopt them. No machine appears to the plaster* men so valuable 
for crushing the coarse rock as the old nipper and coffee mill cracker 
used for over 30 years. In some of the New York mills Blake crushers 
have displaced the old type of crushers, but the number is as yet small. 

It is but natural that appliances used for so long a period of time, 
which make a plaster of high strength and uniform quality, and by which 
in past years the owners of mills have accumulated comfortable fortunes, 
should be displaced only with great difficulty by new methods, theoreti- 
cally improvements, but practically in use but a short time. 

The early experience, filled with failure in the use of rotating cylin- 
ders at Grand Rapids and Alabaster has not been forgotten, so new 
methods reported as successful in New York and Pennsylvania are looked 
upon with suspicion by the practical operators in this State who are 
familiar with the past history of these early Michigan cylinders. This 
experience of opposition to new methods is seen in many lines of industry. 
It was prominent some years ago when rotary kilns were invented for use 
in Portland cement manufacture. 

The buildings in the Michigan plant are built in a substantial manner 
of brick or heavy frame. The older mills are built compact with the 
different rooms under one large roof, or grouped close together. The 
new plants have separate buildings and if not built of brick, have at 

132 GYPSUM. 

least the engine room so constructed. Fire has destroyed many of the 
gypsum mills and every precaution is used to avoid the danger of fire. 

§ 6. Use of Retarders. 

Plaster of Paris made from gypsum rock will set in a few minutes, but 
if a retarder can be added, it will delay the set for a longer time according 
to the amount added. In ordinary cases enough retarder is mixed with 
the plaster in the Broughton mixer to delay the set about two hours and 
occasionally by special order, the set is delayed six to eight hours. The 
retarder a few years ago was always added in the kettle which gave un- 
even and unsatisfactory results. 

Various substances have been used for this purpose. In the earlier 
history of cement plasters, glue water was added by the workman as he 
used the material; but this was troublesome and often resulted in poor 
work from neglect to use the proper amount or failure to thoroughly 
mix the parts. The trade demanded a plaster already retarded in a way 
that would give uniform results. This has led to the invention and manu- 
facture of patent retarders in large numbers. 

These retarders have a base of some glue compound or hair treated with 
chemicals, and are organic in composition. The popular brands now in 
use are the Challenge, Webster City, Wymore, Binn's, Ohio, retarders. 
In Michigan the Wymore retarder is in common use. It is made of a 
mixture of organic compounds not patented, but the formula is carefully 
guarded, and it is made at Wymore, Nebraska. 

Among the ancient Romans, blood was used to retard the set of plaster 
of Paris, and today the organic material of the tankage from packing 
houses is found to give the desired results and is used to a very consider- 
able extent as a retarder. Among the numerous patents issued for re- 
tarders the following may be of interest : 

Patent number 280,650 was issued to cover a mixture of plaster of 
Paris, saw dust, hair, and water. 

Patent number 291,508 is for a mixture of plaster of Paris, weak glue 
water, glycerine, sawdust, and slaked lime. 

Patent number 301,459 is a mixture of plaster of Paris and glue. 

Patent number 445 211 calls for a mixture of a solution of the substance 
of hair. 

Patent number 446,604 is a mixture of beans, peas, and lentils, with 
slaked lime, carbonate of soda, and alkaline earth. 

Patent number 452,346 covers a mixture of plaster of Paris with glue 
dissolved in water, lime slaked in glue water, and sand. 

Patent number 391,889 is for a mixture of plaster of Paris, sawdust, 
sugar, carbonate of so:la, slaked lime, sand, pumice stone. 

Patent number 397,297 is for a mixture of hydraulic lime, animal gela- 
tin, and vegetable glutinous matter. 


Patent number 321,620 covers the mixture of plaster of Paris and resin- 
de-lac dissolved in caustic soda. 

Patent number 420,008 is a mixture of plaster of Paris, serum and hair 
mixed, carbolic acid and air slaked lime. 

Patent number 479,060 is a mixture of plaster of Paris, glue, seed meal, 
sulphate of zinc, cut rope or hair. 

Patent number 523 658 is for the mixture of fermenting and decom- 
posing organic matter in water mixed with quick lime dried and 

Patent number 558:435 gives a complex mixture of plaster of Paris, 
furnace slag, slaked lime, hydraulic cement, flour of grain, and fibre. 

Patent number 502,006 gives plaster of Paris, sanegal gum. sugar, 
silicate, carbonate of soda, alum, clay, salt cake, and ground China meal. 

An examination of these specifications will show considerable re- 
semblance in composition, and part of the materials included would ap- 
pear to be only needed to add to the complexity of the mixture and 
enable one to secure a patent. Plaster of Paris is a common ingredient. 
Of the 40 patent specifications in my possession, 20 have a base of 
glue, and five of prepared hair, seven contain sawdust. 

The cause of the retarding influence of such mixtures has never been 
fully determined. The set of plaster, as will be shown in another sec- 
tion, is due to the formation of a crystal network. This ordinarily 
takes place as soon as water is added to the calcined gypsum. The 
retarder delays in some way this crystallization, possible by holding 
the water, as dried organic tissues have a strong affinity for water. 
The water would then be given up slowly to the plaster and the crystal- 
lization be delayed. 

In the laboratory crystals may be seen forming out of solution and 
then gradually increase in size. This is seen in some substances better 
than in others, but the cause of the phenomena has been a subject of 
speculation from the days of the early mineralogists of the time of 
Hauy at the beginning of the last century, but so far the explanation 
of the exact causes of crystallization has eluded the students of crystal- 
lography. Until the causes of crystal formation are understood, it will 
be extremely difficult if not impossible to explain the action of sub- 
stances which act as retarders to crystallization. 1 

The force which produces crystals has been termed the crystallizing 
force and while this is a useful handle for grouping the observed facts, 
it lacks an explanation and definition. It seems without doubt to be 
a molecular force and is exerted in different ways in different sub- 
stances, and different ways in the same substance under different con- 

'Glues increase viscosity hence retard circulation. The growing crystal soon exhausts its 
immediate neighborhood and new material is ouly slowly fed in. See Rosenbusch p. 28, Mieroscop- 
ische Fhye>ioKrapie. 



The retarder as added to plaster is in proportion of 4 to 6 pounds to 
the ton, or in 1 pound there would be about 1-30 of an ounce, and this is 
sufficient to delay the set 3 or 4 hours. 

If the retarder holds the water as suggested above, the plaster would 
not be injured by such addition of foreign material in small amount, 
as it would only delay the time of the formation, and the resulting 
crystal network would be as strong as though no retarder was there, 
but experiments show that the plaster is weakened, and there must be 
some other result in addition. A series of experiments was made to 
determine the effect of the retarder on the strength of the plaster. The 
following table shows the tensile strength in pounds per square inch 
of plaster of Paris plus Wymore retarder after 30 days. 


Pounds of 
retarder ; 
to ton. 

Initial set. 

Final set. | 





•J min. 

48 min. 1 






10 ' 

3 •• 

1 hour 
23 min. 

1 hour 
8T> min. 

1 hour i 

49 min. j 

7 hours, j 

43 min. • 



With an addition of two pounds of retarder to the ton, the strength 
of the plaster is decreased over (> per cent. This would indicate a 
direct effect of the retarder on the crystal arrangement preventing a 
perfect crystallization of the plaster. The reduced strength even with 
the addition of 10 pounds of retarder to the ton, would still give a 
plaster stronger than is really necessary for a wall, as it would never 
be subjected to a strain of 325 pounds to the square inch. But the 
excess of retarder. would through disintegration probably greatly 
weaken the plaster in course of time. 

The? proper treatment would be to use as little retarder as is neces- 
sary and to use the best that is made. The gelatins to which group 
glue belongs are composed of carbon, hydrogen, nitrogen, and oxygen, 
in very complex proportion, but they represent fairly ^stable com- 
pounds. Some of the refuse matte* used for retarder is of very different 
character and in nature passes through the stages of decay and it seems 
but natural that they would alter even plaster. 

Particles of foreign material added to plaster of Paris appear to act 
as accelerators, but when some of these are heated with the gypsum 
they act as retarders. The table shows a portion of an extended series 
of experiments on intluence on set of plaster through the use of a variety 
of substances. The clay used was ordinary fine ground clay with a con- 
siderable percentage of moisture. This clay burned with the gypsum 


rock held back the set. The dried clay seems to be a retarder and in 
that condition would have a strong affinity for water. 

Initial set Final set 

Mixture of plaster of Paris. in minutes. in minutes. 

Pure plaster of Paris 7 21 

water acidulated with HC 1 2 64 

u H 8 SO« 1* 4 

with sodium carbonate 9 16 

u " sulphate 4* 10 

4i concentrated sugar solution 5 124 

' ' borax 44 12 

% * wood charcoal 7 124 

** limestone 7 ltt 

one-third sand 7 lf> 

• 4 1% limestone 11 23 

<l 6% " 13 24 

" 10* " 10 H» 

*' 2% clav 5 14 

" 8* " 5* 15 

" 10 " 5 15 

An inspection of this table shows that the different proportions of 
clay and even of limestone make but little difference in the time of 
setting. Acids and sulphates when added in nearly saturated solutions 
hasten the set. Sugar solutions were formerly added for retarder, but 
in nearly saturated solution they hasten the set. 

§ 7. The Set of Piaster. 

When water is added to plaster of Paris, it sets in a solid mass. This 
is all that it is necessary for the plasterer to know in order to do his 
work, but to many of these men the subject of the true nature of the 
set is an interesting and puzzling problem. Just what is the process 
of setting of plaster? 

Lammer Theory. 

As far as we. can learn from the chemical and physical literature, 
thiB question was first answered by that famous French chemist, Lavoi- 
sier, who in 1705 described the results of his exjwriments in the follow- 
ing words, translated from the French. 1 

,4 1 took the calcined plaster, as has been described before, and which 
hardens readily with water. 1 threw it into a considerable amount of 
water, in a pan or large dish. Each molecule of plaster, in passing 
through the liquor, seized its molecule of water of crystallization, and 
fell to the bottom of the dish in the form of small brilliant needles, 
visible only with a strong lens. These needles, dried in the free air or 
with the aid of a very moderate heat, arc very soft and silky to the touch. 
If placed on the stage of a microscope, it is perceived that what was 
taken under the lens for needles are also parallelopipeds, very fine, so 
they are described as thicker, or many times thinner, and many more 
elongated. The plaster in this state is not capable of uniting with water, 
but if it is calcined anew, these small crystals lose their transparency 

'Quoted by I.undrin. Annates de Chimie, pp. 431, 436; 1874. 

136 OYPSUM. 

and their water of crystallization, and become again a true plaster, as 
perfect as before. One may, in this fashion, successfully calcine and 
recrystallize the plaster even to infinity, and consequently give it at will 
the property of seizing water." 

This explanation of the set of plaster through the formation of a crys- 
talline network was verified a number of times later, and was given by 
Payen in 1830 as his first principle in the chemistry of plasters. 

Landrin'8 Theory. 

The next important contribution to the chemistry of plaster was by 
Landrin in 1874, who divided the sot of plaster into four periods. 

"1. The calcined plaster, on contact with the water, united with this 
liquid and takes a crystalline form. 

"2. The plaster dissolves partially in water, which becomes saturated 
with this salt. 

"3. A part of the liquid evaporates, due to the heat set free in the 
chemical combination. A crystal is formed and determines the crystal- 
lization of the entire mass; a phenomenon which is analagous to that 
which takes place when a piece of sulphate of soda is placed in a satu- 
rated solution of this salt. 

"4. The maximum hardness is reached when the plaster gains 
enough water to correspond exactly with the formula CaOS0 3 , 2H 2 0; 
this maximum being to the remainder in proportion to the quantity of 
water added to the plaster to transform it into mortar." 

Cliatelier > 8 Theory. 1 

Chatelier in 1887 showed that plaster would set in a vacuum tiask. 
so that evaporation was not a necessary step in the set of plaster, as 
Landrin maintained in his third principle above. 

According to Le Chatelier, the plaster of Paris compound (OaSOj... 
H 2 dissolves in part in the added water, which diminishes the solu- 
bility, and the solution becomes therefore supersaturated and Ca80 4 , 
2H 2 0, or gypsum, crystallizes out. In other words, the plaster of Paris 
dissolves, and becomes hydra ted, then crystallizes out as gypsum, and 
every particle of the plaster goes through these steps. 

Q-rimsley Theory. 

In Volume V of the University Geological Survey of Kansas, the 
writer outlined a theory to explain the setting of plaster. This theory 
was based on a number of laboratory experiments and on careful ob- 
servation. Since that time a considerable amount of time has been de- 
voted to this subject and the theory still appeals to me as a logical 
and plausible one, fully in accord with the observed facts. 

' Academie des Sciences 1887. 



Under the microscope the ground gypsum before calcination con- 
sists of rather large masses of varying size as shown in Figure 31. In 
comparison with the gypsum earth, the rock is seen to consist of more 
or less broken crystals, while the gypsum earth shows crystals of more 
regular shape. After calcination these larger crystals are found to be 
broken into fine granules of nearly uniform size and shape. As the 
material is heated, the water is changed to steam throughout the crystal 

Fig. 31. Uocalcioed gvpsum eartb, X 500 Fig. 32. Calcined gypsum earth from central 

diameters. Kansas, one-half hour after water was added 

to it, X 80U diameters. 

mass, and expanding, breaks the crystals into finer particles. There is 
thus a physical change as well as a chemical one. If the plaster has 
not been sufficiently calcined the grains are coarser and more irregular. 

Under the microscope when water is added to the calcined plaster, 
small needle like prisms are seen forming and shooting out here and 
there. As these become more and more abundant, they unite with one 
another and rapidly form a solid mass, in which the individual crystals 
can scarcely be distinguished. Open spaces, are left in the mass appar- 
ently filled with water, and finally these are closed, and a firm solid mass 
results. The network formed by these crystals at first, is shown in (he 
drawing in Figure 32. 

The treatment of calcined gypsum with water in the same way shows 
very little change. Figure 33. Gypsum crystallized from solution by evap- 
oration shows crystals which are not needle shaped, but they are broader 
and show considerable irregularity. They are more or less twinned and 
they do not interpenetrate, but form a loose mass which readily crumbles. 
This crystallization is shown iti Figure 34, which was obtained by evapor- 
ating a solution of unealdned gypsum on a glass slide and then examin- 
ing it under a high power microscope. 

Crystallization is aided by the small size of the grains or particles 
in the plaster, and the finer grained plasters set more rapidly than the 
coarser ones, as one may observe in the fine dental plasters as com- 
pared with ordinary plaster of Paris. 



My own experiments agree then with those given by Lavoisier, Payen, 
Landrin, and Chatelier, in that the set of plaster is due to the forma- 
tion of a crystalline network. The cause of the formation of this net- 
work of crystals, or the factor which starts the crystallization is the 
troublesome part to explain, and this has attracted less attention among 
investigators along these lines. 

When gypsum is burned it forms, as Landrin showed and as analyses 
prove, the hydrate (CaS0 4 ) 2 , H 2 0. Marignac called attention to the 
fact that if the water is added in excess, this hydrate in part is dis- 
solved, forming first a clear liquid which then becomes turbid, and 
crystals of CaS0 4 , 2H.X3, or gypsum are thrown down. Now an exami- 
nation of these formula? shows that three parts of water have been 
taken up by the hydrate. 

Fit.. 38. Uncalcined ground gypsum in waiter, 
after Kttuidinp three days. 

Fig. M. Gypsum crystallized from HOlution in 
water, after stai dioir three day 8. 

(CaS0 4 ) s , HoO + 3H 2 = 2 (CaS0 4 , 2H 2 0). 

So first the plaster dissolves partially in contact with the water, as 
Landrin pointed out in his second principle, and as accepted by Chatelier. 
Next, some changes take place whereby, according to Mariginac's ex- 
periment, the liquid becomes turbid and crystallization begins. Landrin 
thought evaporation took place as a result of the heat formed by chem- 
ical combination, and that then a crystal was formed which started the 
crystallization through the entire? mass. Chatelier showed by experi- 
ment that evaporation was not necessary and he argued that by the 
taking up of this water the solubility of the hydrate was decreased, 
and so, on account of the resulting supersaturation, crystallization 

The solution of the hydrate in these experiments is certainly saturated, 
and all that is needed is something to start the crystallization. From 
a study of saturated solutions in the laboratory, it is well known that 
if crystals are introduced into such solutions crystallization will result 
and go on until the salt is crystallized out. 


The effect of beat on gypsum in the burning of plaster, as we have 
sbown, is to remove a certain percentage of water and to break up the 
small masses of the rock into liner and finer particles, microscopic and 
ultra-microscopic in size. If the heat is not carried too far certain par- 
ticles through the mass may still possess their crystalline form as shown 
in Figure 31, and so they are true crystals though very small. These 
minute crystals in the saturated solution would start the process of 
crystallization. Their growth would cause the turbidity of the solution 
as noted by Marignac,* and would result in the precipitation of small 
gypsum crystals, thus forming the crystal network which constitutes 
the set of plaster. 

Fig. 35. Calcined gypsum earth from central Kansas, ■ 500. 

If the plaster is unburned the gypsum is not reduced to the proper 
fineness and uniformity, and so would not permit the crystallization 
to go on in the way it would in the properly burned plaster. But of 
more importance, the hydrate represented by plaster of Paris would 
not be formed. 

If the plaster is overturned, the plaster will be so completely com- 
minuted that no minute crystals would be left to start the crystalliza- 
tion. Where the plaster is slightly overburned, the crystals are ex- 
tremely fine and crystallization goes on very slowly and imperfectly. 



§ 1. Composition. 

Gypsum was used in a variety of ways long before its real nature and 
composition were determined or even investigated. The first record of 
the composition of gypsum is found in a paper of Lavoisier presented to 
the Academie des Sciences in 1705. Lavosier decomposed the gypsum 
rock by means of carbon, setting free sulphurous vapors which formed 
a sulphur deposit and proved the presence of sulphuric acid. He then 
decomposed a solution of gypsum in water by means of potash, showing 
the presence of lime. In this manner the qualitative analysis of gypsum 
rock was made and its elements determined. 

Later quantitative analyses were made on various specimens of gyp- 
sum. One of these early analyses was made on pure crystallized gypsum 
from Mont-martre near Paris. This analysis shows a very low percentage 
of water, and indicates rather anhydrite. 

Per cent. 

Silica 0.02 

Lime sulphate 92.56 

Lime carbonate * 0.32 

Water 7.10 


From this and other similar analyses, the theoretical composition of 
a pure gypsum was determined, and by later revision was given as, 

Per cent. 

Sulphuric acid 46.60 

Lime oxide 32.50 

Water 20.90 


The perceutage composition of water (20.9) and lime sulphate (79.1). 
divided, respectively by the atomic weights (water) 18, and (lime sul- 
phate) 135, would give a proportion of the groups in the molecule, for 
water as 1.162 and for lime sulphate as .585, or a relation of two parts 


of water to one of lime sulphate expressed by the chemical formula 
OaS0 4 , 2H 2 0. When the two parts of water are absent the mineral is 
called anhydrite. 

A portion of the water in the gypsum is readily removed on applica- 
tion of heat, and observation accompanied by chemical analysis shows 
that about three-fourths of the water can be readily removed, and the 
other one- fourth only with difficulty; and further that the three- fourths 
so removed passes off at two different stages. 

§ 2. Payen's Experiments. 

The facts noted above were first determined by Lavoisier and con- 
firmed by Payen 1 in 1830, who found that the gypsum began to lose 
water at a temperature of 115° C, and that the loss rapidly increased 
up to 204° C. He determined the best temperature for the formation 
of plaster to lie between 110 and 120° C. (230 to 248° P.). In modern 
plaster manufacture a temperature of 100° or more higher than Payen's 
is used. 

Payen's results are given in the following summary: 

1. The set of plaster is due to a crystallization of hydrous sulphate 
of lime. 

2. The lowest temperature at which plaster can be made is 80° C. 
(176 * F.), but the material must be kept at this temperature for a con- 
siderable period of time. 

3. A temperature of 110 to 120° C. is sufficient to deprive plaster of 
all its water and to calcine it completely. 

4. Plaster in small particles favors drying. 

5. Calcium sulphate heated to about 250° C. (482° F.) is dehydrated; 
at 300 to 400° C. (572 to 752° F.) it loses completely the properties of 
hydration, or the power of gaining again the water of crystallization, 
and resembles then the hydra ted sulphate of lime found in nature. If 
heated higher, it may result in melting the sulphate of lime. 

6. The hardening of plaster by alum is perhaps due to the forma- 
tion of a double sulphate of potash and lime. 

§ 3. Chatelier's Experiments. 

Chatelier 8 in 1887 conducted some very elaborate experiments on the 
effects of temperature on gypsum. He powdered the gypsum rock and 
placed it in a paraffin bath, and connected a thermometer in the bath 
with a chronograph. On applying heat up to 200° C. or 392° F., there 
was a constant rise in temperature, with two exceptions. The first halt 
occurred at 128° C. or 262° F., and the second at 163° C. or 325° F. 
The first one was the more pronounced, and Chatelier regarded these 

■Qitmle Industrielle, 1880. quoted by Landrin, Ann ales de Chimie, 1874. 
* Annates des Mines, p. 345, 1887. 

142 -GYPSUM. 

interruptions as due to an absorption of heat which accompanied the 
elimination of water. This would indicate the existence of two different 
hydrates, whose decomposition took place at the temperature! indicated 
by the halts on the chronograph. Further the dehydration was found 
to be incomplete at 155° C. or 311° F., and complete at 194° C, or 
381° F. 

In order to prove the composition of the first hydrate, Ohatelier heated 
a saturated solution of gypsum in a closed tube to a temperature be- 
tween the two halts indicated, or between 130° C. (266° F.) and 150° 0. 
(302° F.) and very delicate, long, rectangular prisms were formed, which 
were thrown into alcohol and then analyzed with the following result : 

Per cent. 

Water 6.70 

Sulphate of lime 93.30 


This agrees very closely with the formula (CaS0 4 ) 2 , H 2 0, where there 
would be, 

Water 6.20 

Sulphate of lime 93.80 


In this compound it is seen that two parts of lime sulphate are united 
with one part of water, while in the original gypsum one part of lime 
sulphate was united with two parts of water. Chatelier also found that 
the incrustation in the boilers of ocean steamers, where salt water was 
used and where the temperature averages about 165° C. (320° F.), pos- 
sessed nearly the same composition as the hydrate given above. His 
analysis was as follows: 

Water 5.80 

Sulphate of lime 91.90 

Carbonate of lime 0.30 

Iron oxide 2.00 


Further experiments by Chatelier showed that if 10 grammes of 
powdered gypsum were heated for some time at 155° C. or 311° F., in- 
termediate between the temperatures necessary for the decomposition 
of the two hydrates, the loss in weight was uniformly 1.56 grammes 
which corresponds with one and a half equivalents of water so that the 
compound should contain about 6.2 per cent of water as shown by the 
formula given. Ordinary plaster of Paris usually contains about 7 per 
cent of water, so that it is a definite hydrate with the formula 
(CaS0 4 ) 2 , H 2 0. 


The second halt, as has been given, took place at 163° C. or 325° F. 
From this temperature to 221° C. or 430° F. no change was noted in 
the plaster; but beyond this temperature, the plaster when mixed with 
water did not absorb it readily and only set after a long time. If the 
heat reaches 343° C. or 650° F., the plaster acts like anhydrite, and it 
is said to be dead burned and will not set on addition of water. If the 
gypsum is heated further, the substance melts, forming a crystalline 
mass on cooling which cannot be decomposed by heat except in the 
presence of organic matter, when it changes into CaS. If this sub- 
stance is acted upon by carbon dioxide gas (OCX) and water, sulphuretted 
hydrogen gas will be formed. 

The temperature of burning is thus seen to be all important, and 
calls for skill and experience on the part of the calciner. If overburned, 
the plaster sets very slowly. If underburned, the new hydrate is not 
formed, and the plaster will not set. 

§ 4. Chemistry of Foreign Gypsum. 

In the various papers on foreign gypsum deposits so far as consulted, 
very few analyses are given. The gypsum of the Hartz 1 mountains is 
a pure variety containing but little silica and iron, while the analysis 
from the Philippines shows a higher percentage of the silica impurity. 

Wi*»nrode Osterode Albany 

Hartz Huru Philippine* 

by Jungst. by Hampe by Trobe. 

Silica and insoluble residue 2.80 0.1f> 6.43 

Iron and alumina oxides 0.60 0.64 

1 ime sulphate 77.63 79.05 73.60 

Lime carbonate 

Water 19.90 20.74 20.18 

100.93 99.94 100.85 

In New South Wales* the gypsum is not as yet used to any extent, and 
may be compared with the rock on St. Marcos island off the coast of 
California analyzed by the writer, and also with the analysis of the 
gypsum of Hawaii. 

Lake Tank, 
north of 
New South St. Marco*. 

Wales by Grirasley. 

Silica and insoluble residue 2.90 0.16 

Iron and alumina oxides 0.60 0.31 

Lime sulphate 75.66 78>0 

Lime carbonate 0.93 

Water 20.20 20.31 

Magnesia sulphate 0.61 

99.97 100.31 

>C»l<*ula l ed from analyses tfiven in VoL V, Univ. Cieol. Survey. Kans.. p. 141. 
* Minerals of New South Wales, p. 164, 1888. 

144 GYPSUM. 

The analysis from Hawaii 1 shows a very high percentage of lime, and 
would give about 76.04 per cent of lime sulphate, and leave about 7 per 
cent for water, i. e., anhydrite. 

Silica aDd insoluble residue 4.00 

Iron oxide (Fe* O a ) 0.70 

Lime oxide 43.40 

Sulphuric acid 44.73 

Magnesia oxide 0.50 


§ 5. Canada Gypsum. 

In Canada over four-fifths of the gypsum quarried is exported, and 
most of this rock comes to the United States. The leading district for 
the gypsum sent to this country is in Nova Scotia. Analyses* of this 
rock are given in the following table which shows the percentage of 
sulphuric acid and also the calculated percentage of the combined sul- 
phate of lime plus water. 

No. 1. No. 2. No. 3. No. 4. 

Sulphuric acid 43.65 43.98 40.84 44.86 

Water 18.47 20.02 

Insoluble in acids 1.88 2.67 0.99 2.57 

Undetermined 4.28 2.77 11.20 0.97 

Sulphate oflime and water (jrypsumK 94.84 94.56 87.81 96.46 

101.00 100.00 100.00 100.00 

§ 6. United States Gypsum. 

The gypsum rock from eastern United States to the Pacific coast 
shows a considerable range in chemical composition. In the eastern 
part in New York state Ihe composition is shown in the following 

N. Y. Rock, s 
Cayuga.! Onondaga. •» Prof. Armsby. 

Lime sulphate and water (gypsum).. 74.09 64.53 73.92 76.35 

Insoluble matter 6.05 11.17 4.64 5.83 

Other material chiefly CaCO, 19. M> 24.27 21 .44 17.82 

100.00 99.97 100.00 100.00 

The average composition of the New York gypsum rocks is given 
by Merrill as, 

Land plaster.* Severance quarry. • 

Lime sulphate and water (gypsum) 65 to 75$ 80 to 90$ 

Insoluble material 6 to 8$ 10$ or less. 

Lime carbonate 18 to 28$ Trace. 

Magrnesia carbonate 5$ or leas. 

M9 Annual Report U. 8 Oeo'ovical Survev. Part VI, Cont., p. 685: 1897-8. 

*Rcportof «'onneetiotit Exp Station, p. «2: 1883. 

''Report Connecticut, Exp. Station, p. 75; 1884. 

< *• of HHme station, p «2: 1883. 

*Adv»rtistn* Circular Marsh & ^o., Sandusky, Ohio. 

«Roport Connecticut Exn. Station, p 50: 1882. 

'Bulletin New York State Museum. Vol. lit, p. 81; 1893. 

ANVdwoo naisvid saiavH qnvmo ^wnsdAO nNiaNran s-niw axcxis hh:ih 

niAX »1«M II W«j XI IOA 

•uTUiiqotfv i° AaAjns [UOjSoioao 



Going farther west, the gypsum industry is seen to center in a small 
district near Sandusky in Ohio. This rock, according to the late Pro- 
fessor Orton, has the following composition :' 

Average Surface Land 

sample. rotten rock. plaster. 

Silica and insoluble material 0.68 0.46 0.91 

Iron and alumina oxides 0.16 0.29 0.60 

Lime sulphate 77.45 78.54 78.73 

Lime carbonate 1.12 0.75 

Water 20. 14 20.00 19.70 

Magnesium oxide 0.56 0.03 0.54 

100.11 100.07 100.48 


An analysis of a gypsum deposit in Florida is given by Dr. David T. 
Day, as,' 

Per cent. 

Silica and insoluble material 0.07 

Iron and alumina oxides 0.01 

Lime sulphate 77 . 79 

Lime carbonate 0.52 

Water 21 . 39 


The composition of the Iowa gypsum is given in the following analyses 
by G. E. Patrick : a 

sample. Top. Middle. Bottom. 

Insoluble residue 0.65 

Lime sulphate 78.44 78.37 78.54 78.44 

Water (calculated).... 20.76 20.75 20.79 20.76 

99.85 99.12 99.33 99.20 


In Kansas a very complete chemical examination was made by Prof. 
Bailey of the gypsum rocks and plasters. From these a few are selected 
to show the range in composition of the gypsum rock, and a second 
series gives the composition of the gypsum earth so much in demand 
in that section for the manufacture of plasters. 4 

i Calculated from Geol. Survey of Ohio. Vol. VI. pp. 605-702; 1888. 
(Calculated from U. S. Geol. Surrey. Vol. XX, Part VI Cont., p. 662; 1890. 
•Iowa Geological Survey. Vol. Ill, p. 291; 1806. 
4 Univ. Geol. Survey of Kans., Vol. v., pp. 146-147; 1800. 




Blue Rapids. 

Silica and insoluble material 0.65 

Iron and alumina oxides 0.17 

Lime sulphate 79.30 

Lime carbonate 1.53 

Water 18.84 

Magnesium carbonate 0.39 



















Kansas Gypsum Earth. 1 


Silica and insoluble material 12.13 

Iron and alumina oxides 0.99 

Lime sulphate 64.63 

Lime carbonate 3.57 

Water 18.75 

Magnesium carbonate 0.88 


















Oklahoma, Indian Territwy, and Texas Gypsum Earth. 

Marlow. Okarche, Quanah, 

I. T.2 O.T.8 Tex. * 

Silica and insoluble material 10.67 7.98 0.91 

Iron and alumina oxides 0.60 0.50 0.21 

Lime sulphate 59.46 71.70 69.92 

Lime carbonate 10.21 1.14 9.05 

Magnesium carbonate 1.10 0.24 0.65 

Water 16.59 18.68 18.85 





Aspen District, 

Silica and insoluble material 1.46 

Iron and alumina oxides 

Lime sulphate 69.26 

Lime carbonate 5 .96 

Water (calculated) 21.50 

Magnesium carbonate 1 . 32 


Red Buttes. 








The gypsum deposits of California have been worked from time to 
time, but at the present time only one deposit is worked and this is 
near Los Angeles. The analvses are given as follows: 7 

1 Univ. GeoL Survey of Kansas, pp. 149, 152, 154. 

» Univ. Geol. Survey of Kansas, Vol. V., p 149; 1899. 

■ Furnished by the O. K. Cement Plaster Co. 

« Wilkinson, The Technology of Cement Plaster, p. 5; 

b Calculated from U. S. Geol. Survey, Mono., XXXI, 

e Furnished by Prof. Wilbur C. Knight. 

7 Univ. of California Exp. Station, 1891-2. 

; 1897. 

p. 240; 1898. 













1 00.0 







No. 1. No. 2. No. 3. No. 4. No. 5. No. 6. 
Silica and insoluble material . . 
Calcium sulphate and water. . 

Calcium carbonate 

Other materials 

No. 1, Coalinga. No. 2, Nevada Gypsum and Fertilizing Co. No. 3, 
Bakersfield mine. No. 4, Southern California. No. 5, San Francisco. 
No. 6, Los Angeles. 

A comparative study of these various analyses shows that the range 
of gypsum (lime sulphate and water) varies from 04.53 per cent at 
Onondaga, N. Y., and 72 per cent in Southern California, to 99.18 on 
Bear Island, Florida and 99.50 in Iowa. 

The gypsum of Florida, Iowa, Ohio, Kansas, will average close to 99 
per cent purity. The Canada gypsum will run about 94 per cent. The 
California rock gypsum runs about with the gypsum earths of Wyoming, 
Kansas, Oklahoma, and Texas, ranging from 80 to 85 per cent. 

The silica impurity is under 1 per cent in Ohio, Florida, Iowa, and 
Kansas; but according to the analyses given it is 4 to 6 per cent in 
New York, and up te 14 per cent in some of the California rock. Lime 
carbonate ranges around 1 per cent in most of the gypsum rock of the 
United States. The theoretical percentage of water is 20, and the rocks 
analyzed show a per cent ranging from 17.82 to 24.27. 

The average per cent of lime sulphate and water, or gypsum in the 
analyses of the U. S. gypsum rock quoted in the preceding analyses is 
92.75; or leaving out the New York and California analyses would give 
97.38 per cent. 

The difference in percentage of lime sulphate in favor of some deposit* 
is often taken advantage of, for advertising purposes, but the gypsum 
in this country is usually of high grade of purity in the areas worked 
for plaster, and makes a good product. The centralization of the plaster 
industry in certain states is due not so much to the purity of the 
material, as to the extent of the deposits, nearness to railroad markets, 
and to the business enterprise of the people forming the companies. 

§ 7. Chemistry of Michigan Gypsum. 

Having passed in review the chemical nature of the various gypsum 
deposits in this and other countries, it now remains to examine the 
deposits of this state, where gypsum of marked purity can be found, 
and where one of the leading centers of the industry is established by 
the causes given in the preceding paragraph. 

The chemistry of Michigan gypsum has been discussed from the be- 
ginning of the industry. Some of the old records hasten to state that 
the gypsum of this state is the purest in the country, a statement 
naturally disputed by the workers of other states. In any section it 

148 GYPSUM. ^\ 

is possible to select exceptionally pure sf>ccimens of gypsum rock whose 
analysis approaches very closely the theoretical percentage called for 
by the formula. On the other hand it is possible to select portions of 
rock impregnated with clay and other impurities which will give an 
analysis showing an exceptionally poor rock. In making comparative 
examinations, or in giving the composition of a quarry, it is essential 
that careful samples be taken not from one place alone, but from dif- 
ferent parts of the quarry. Not knowing in all cases just how the speci- 
mens were selected from which the analyses were made as given in the 
foregoing pages, it would not be just to draw conclusions as to the best 
deposits in the country, or to say where the poorest are found. Again 
the effect of tin* so-called impurities is not always known. Some of 
these may be beneficial. Lime carbonate in marked quantity in gypsum' 
is usually regarded as a useless impurity in this country; but in the 
Paris gypsum the 12 per cent of lime carbonate is said by some authori- 
ties in that country to explain the greater strength of Paris plaster 
over the plaster in some other countries. The presence of alumina in 
amounts of two and three per rent is said to act as a retarder in the set 
of plaster. 

Method of Sampling. 

In the present work, an attempt was made to secure average samples, 
and this was accomplished by taking the specimens from the spouts 
into the buhr mills. This partially crushed rock coming from various 
parts of the quarry represents the rock actually ground and made into 
plaster. An amount of about two or three pounds weight was taken 
and divided. The part selected was again divided and crushed to a 
fine Hour, and then divided and a portion ground to the finest powder 
in an agate mortar. One gram of the powder was taken for analysis. 
This method would give a lower proportion of the compounds than 
would be given by carefully selected pure specimens. The results 
may not be so valuable for advertising purposes when compared with 
analyses made* from carefully selected samples in other districts, but 
should compare well with those made by the chemists of our state 

The samples collected for the Kansas work were selected in a some- 
what different way, but with the same object in view of determining the 
average quarry composition. In that state the specimens collected by 
the writer, were taken from various parts of the quarry, crushed and 
then divided two or three times and a few pounds weight were taken 
and sent to the laboratorv where it was further divided and crushed. 


Metlvod of Analysis. 

The method of analysis used on the Michigan material is based on 
the methods used by Prof. Bailey of the Kansas work and was as fol- 

One gram of the powdered gypsum was dissolved in concentrated 
hydrochloric acid in an evaporating dish and evaporated to dryness on 
a sand bath until all odor of HC1 had disappeared. The mass was then 
digested with dilute acid and boiled several times. A single boiling 
was found to leave a heavy apparently insoluble residue, which was 
greatly decreased on the second and third boiling. This portion of 
the analysis should be watched carefully so as to make sure that the 
lime sulphate all goes into solution. The solution is then filtered and the 
silica or insoluble material on the filter is washed with hot water, dried, 
ignited and weighed. 

The filtrate is diluted to 500 c.c., and thoroughly mixed; 300 c.c. are 
taken for the determination of the bases, and 200 c.c. for sulphuric acid. 
In the first portion iron and alumina are precipitated with ammonia, and 
the precipitate filtered, washed with hot water, dried, ignited, and 
weighed. To this filtrate heated to boiling is added a hot solution of 
ammonium oxalate and the precipitate of oxalate of lime after stand- 
ing a few hours is readily filtered, and after drying may be treated with 
sulphuric acid (H 2 S0 4 ) converting the oxalate to sulphate of lime which 
multiplied by 7-17 will give the amount of oxide of lime (CaO). The 
magnesia if present in the filtrate is precipitated with sodium phosphate, 
which, filtered, dried, weighed, and multiplied by .750 will give the 
amount of (MgO), magnesium oxide. 

The other portion, 200 c.c. treated with barium chloride ( BaC^ will 
give a precipitate of barium sulphate (BaSOj, whose weight multiplied 
by .3435 will give the amount of sulphuric anhydride (SO). 

One gram of the powdered gypsum heated in an open platinum cruci- 
ble to a temperature of 200° C. will give a loss in weight representing 
the amount of water. 

Such an analysis of a specimen of gypsum will give the simple com- 
pounds which can be united to show the probable composition of the 
rock. The sulphate of lime will equal the amount of sulphuric anhydride 
plus the amount of lime oxide equal to the sulphuric anhydride multi- 
plied by .7, and the remaining portion of the lime oxide is probably com- 
bined with carbon dioxide (CO.) whose amount may be determined by 
multiplying it by 11-14. 

150 GYPSUM. 


Western Michigan. 

The analysis of the Alabastine quarry rock selected by the method 
given shows the following percentages: 

Per cent. 

Silica and insoluble material 1.28 

Iron and alumina oxides 1 .S25 

Lime oxide 32.94 

Sulphuric acid (SO y ) 44.097 

Water 19.00 

Magnesium oxide trace 


By calculation of this analysis the probable composition of the rock 
would be: 

Per cent. 

Silica and insoluble material 1 .28 

Iron and alumina oxides 1.825 

Lime sulphate 75.984 

Lime carbonate 1 .951 

Water 19.00 

Magnesium carbonate trace 


The lower course of rock in this quarry, red in color, was formerly re- 
jected as being too impure for finished plaster and was only suitable 
for rough uses as land plaster, but at the present time this rock is used 
with the rest of the quarry rock. Its analysis shows that the red color 
is not a badge of impurity. 

Per cent. 

Silica and insoluble material 0.505 

Iron and alumina oxides trace 

Lime oxide 32.90 

Sulphuric anhydride (S0 3 ) 45.114 

Water 20.57 


The analysis would give a probable rock composition of: 


Silica and insoluble material 0.505 

Iron and alumina oxides trace 

Lime sulphate 76.74 

Lime carbonate 2.39 

Water 20.57 



Across the Grand river from the Alabastine quarry in the English 
shaft mine, the gypsum rock has practically the same composition. 

Per cent. 

Silica and insoluble material 1.18 

Iron and alumina oxides 1.87 

Lime oxide 32.74 

Sulphuric anhydride 44.72 

Water 19.00 

Calculating the probable composition of the rock gives: 

Per cemt. 

Silica and insoluble material 1.18 

Iron and alumina oxides 1.87 

Lime sulphate 76.02 

Lime carbonate 2.57 

Water 19.00 


In the same neighborhood a short distance east is the cave mine of 
the Grand Rapids Plaster Co., mill No. 2, where the rock has the fol- 
lowing composition: 

Per cent. 

Silica and insoluble material 1 .245 

Iron and alumina oxides 0.495 

Lime oxide 33.115 

Sulphuric anhydride 45.40 

Water 1 9.03 


Calculating this analysis, gives the probable composition of this 
rock as: 

Per cent. 

Silica and insoluble material 1.245 

Iron and alumina oxides 0.495 

Lime sulphate 77.186 

Lime carbonate 2.380 

Water 19.03 


Passing to the southwest five miles at Grandville, the Durr quarry 
rock has a composition as indicated in the analysis below: 


Silica and insoluble material 1.06 

Iron and alumina oxides 0.325 

Lime oxide 33.095 

Sulphuric anhydride 44.13 

Water 19.72 


152 GYPSUM. 

The probable composition is then: 

Per cent. 

Silica and insoluble material 1.005 

Iron and alumina oxides 0.325 

Lime sulphate 75.017 

Lime carbonate 3.936 

Water 19.72 


The bright selenite plates found in this quarry do not show much 
purer composition than the compact rock. 

Per cent. 

Silica and insoluble material 0.35 

Iron and alumina oxides 

Lime oxide 32.78 

Sulphuric anhydride 45.61 

Water 20.59 


Per cent. 

Silica and insoluble material 0.35 

Iron and alumina oxides 

Lime sulphate 77.537 

Lime carbonate 2.085 

Water 20.59 


Winchell in the I860 report, 1 (pp. 163 and 164) gives the following 
analyses of the Michigan gypsum: 

Silicic acid trace 

Alumina and iron oxide 5354 3.89 loss 

Lime oxide 32.0385 32.67 

Sulphuric acid (S0 3 ) 46.2257 44.44 

Potassia 2115 

Soda 0140 

Chlorine 0078 

Water 20.8445 19.00 

99.8774 100.00 

i The one by L. R. Fisk, the second by S. P. Duffleld. 

Geological Survey of Michigan. 

Vol. IX Part II Plate XIX. 




In the Alabaster quarry, probably the largest gypsum quarry in the 
United States, the average analysis shows the following composition: 

Per cent. 

Silica and insoluble material 0.555 

Iron and alumina oxides trace 

Lime oxide 33.155 

Sulphuric anhydride 45.745 

Water 20.28 

Calculated : 

Per cent. 

Silica and insoluble material 0.555 

Iron and alumina oxides trace 

Lime sulphate 77.766 

Lime carbonate 1.86 

Water 20.28 


Selected material from this quarry shows great purity, as given in the 
following analysis by Geo. H. Ellis, who states it is the finest gypsum he 
has ever analyzed. It would be possible to select a large quantity of 
such rock from this quarry. 

Per cent. 

Lime sulphate 78.67 

Water 20.98 


St. Ignaee. 

The deposits of St. Ignaee in northern Michigan were analyzed, though 
only a small amount of material was available for the examination. 

Per cent. 

Silica aud insoluble material 0.195 

Iron and alumina oxides 

Lime oxide 32.795 

Sulphuric anhvdride 45.845 

Water 20.32 


154 GYPSUM. 

Calculating the probable composition of this rock gives: 

Per cent. 

Silica and insoluble material 0.195 

Iron and alumina oxides 

Lime sulphate 77.936 

Lime carbonate 1.257 

Water 20.32 


At Grayling in the deep well, gypsum was found with a thickness re- 
ported as 132 feet, at a depth of 408 feet. This was analyzed as follows: 

Per cent. 

Silica and insoluble material 19.08 

Iron and alumina oxides 0.31 

Lime oxide 29.755 

Sulphuric anhydride 31.297 

Water 14.10 


This gypsum is evidently a gypsum rock mixed with lime stone, and 
calculated gives: 

Per cent. 

Silica and insoluble material 19.08 

Iron and alumina oxides 0.31 

Lime sulphate 53.20 

Lime carbonate 1 3.92 

Water 14.10 


The Michigan gypsum rock is seen from these analyses to range from 
94.73 to 98.26 per cent of sulphate of lime and water, or in selected 
samples 99.65 per cent, with an average of over 97 per cent. This is 
slightly below the average in Ohio, Iowa, and Kansas. The real explana- 
tion of the difference is to be found in the excess of lime carbonate 
over the localities in Ohio, Iowa, and Kansas. 

The silica impurity is but little over 1 per cent, and it is often less 
than this amount. 

In calculating the probable percentages of the rock, the analyses 
usually run over the 100 per cent. This is explained in the Kansas 
gypsum by Bailey as due to a combination of some of the lime with 
the silica, which is decomposed in the process of getting the mineral 
into solution. It being impossible to tell how much of the lime to add 
to the silica, it was all computed as united with carbon dioxide (C0 2 ) 
in the form of carbonate of lime; and this gives a slight excess in the 
total of the compounds. 


Anhydrite Analyses. L. 

It will be noticed that I have stated that most of the calcium sulphate 
constituents at a considerable depth in wells, such as those of Alma, Mt. 
Pleasant, and Midland, and the series of the deeper wells in the Saline 
along the Detroit river, St. Clair river and the shore of Lake Michigan, 
is anhydrite. This is mainly based upon microscopic determinations. 
However, Mr. H. R. Browne of the Michigan Alkali Works at Wyan- 
dotte, made some tests of samples of their well (Ford No. 23) showing 
that the so-called gypsum is at least largely anhydrite. As the samples 
come up wet, a certain admixture of gypsum may come very easily from 
the water. We have also the results of an analysis of a sample from Mt. 
Pleasant as follows: 

Analysis by M. A. Cobb. Oct. 26, 1903. of sample taken at 1,225 to 1,270 
feet depth. 

Per cent. 

FeA ) 

ALA \ 


CaCO ;J 




CaS0 4 



Si0 2 , CO, ) 
Moisture \ 


100 00 
The Michigan gypsum rocks are of high grade of purity and the plasters 
made from these rocks are standard products in the market. 
§ 8. Chemistry of the Finished Plasters. 


Plaster of Paris in France? 

Iron and Lime Lime Mag. 

Silica. Alumina. Sulphate. Carb. Carb. Water. 

Vintry (Seine), ordinary... 4.9 2.5 70.9 10.2 5.05 6.45 

fine 3.7 2.7 72.6 12.0 5.45 3.55 

Villejuif (Seine) 4.8 0.6 77.95 8.5 1.9 6.25 

Bondy (Seine), ordinary.... 1.4 1.5 79.05 9.9 2.3 5.85 

11 fine 2.4 1.0 83.4 6.9 2.3 4.0 

Romainville (Seine) 0.6 0.8 87.7 2.4 2.7 5.8 

Bois le Comte (Seine) 1.2 0.35 85.75 4.3 .... 8.4 

Lamarche 1.6 .... 88.45 3.75 .... 6.2 

Bussiere 1.05 0.45 84.0 7.15 0.4 6.95 

Roquevaire (Bouches du 

Rhone) 11.2 3.1 70.55 6.7 5.65 2.8 

Bassin de la Couze (Dor- 

dogne) 4.0 1.4 71.60 14.1 5.05 3.85 

Herepain (Herault) 4.2 1.0 81.6 13.2 

Partel (Aude) 0.7 0.4 86.85 5.3 .... 6.75 

Malancene (Vaucluse) 0.6 92.0 0.35 .... 6.15 

Poligny ( Jura) 0.8 .... 93.5 3.4 .... 3.3 

Grasse(Alpes-Maritime8)... 0.1 0.2 95.65 4.05 

i Quoted from M. Durand Claye. Catalogue de Expos, de 1876, in Thorpe's Dictionary, Vol. I. p. 470 

156 GYPSUM. 

Ohio Calcined Plaster. 1 

No. 1. No. 2. 

Silica and insoluble material 0.68 0.46 

Alumina 0.16 0.29 

Lime sulphate 77.45 78.54 

Lime carbonate 1.11 0.75 

Water 20.14 20.00 

Magnesia 0.56 0.03 

100.10 100.07 

These analyses though given for calcined plaster were probably of 
uncalcined gypsum as indicated by the water percentage. 

Wyoming Plaster. 

The cement plaster made at Laramie, Wyoming, according to Slosson 
and Moudy has the following composition : = 

Per cent. 

Silica and insoluble material 5.50 

Alumina oxide 0.59 

Lime sulphate 73.73 

Lime carbonate 7.86 

Water 6.93 

Magnesium carbonate 3.04 

Lime oxide 2.35 


Kansas Cement Plasters. 

The gypsum plasters in Kansas are made from the rock and from the 

gypsum earth. These have been analyzed by Prof. Bailey with the fol- 
lowing results: 3 

Blue ttapidb Spring v ait; 

Rock. Earth. 

Silica and insoluble material 1.20 4.27 

Iron and alumina oxides 0.20 0.47 

Lime sulphate 89.42 83.55 

Lime carbonate 1.08 3.07 

Water 6.S2 6.67 

Magnesium carbonate 1.18 1.47 

100.50 99.50 

i Calculated from analyses in Mineral Resources. U. S. Geol. Survey, p. 600; 1887. 
• Tenth Annual Report Agricultural College of Wyoming, p. 8; 1900. 
8University GeoL Survey of Kansas, Vol. V, p. 1«0; 1899. 


Texas and Oklahoma Territory* 

Okarche, Quanah, 

O. T. Tex. 

Silica and insoluble material 13.29 2.53 

Iron and alumina oxides 0.71 0.45 

Lime sulphate 7S.67 78.81 

Lime carbonate 4.77 11.22 

Water 5.78 5.70 

Magnesium carbonate 1.91 0.74 

100.13 99.45 

Heat of the proper degree applied to the gypsum rock changes it to 
plaster of Paris, through the loss of approximately three-fourths of the 
water. The formula of the calcined plaster (CaS0 4 ) 2 , H..O, calls for 6.2 
per cent of water and 93.8 per cent of calcium sulphate as has been 
explained in the early part of this chapter. 

Many of the Paris plasters approximate very closely the theoretical 
percentage of water, but are usually low in the percentage of sulphuric 
anhydride as are all commercial plasters through the included impuri- 
ties in the gypsum rock. The lime carbonate present in the rock is 
in all probability not altered in the change as the temperature is not 
sufficient to drive off the carbon dioxide (C0 2 ). 

The Ohio analyses though given for calcined plasters were incor- 
rectly labelled or the title represents a mistake in the proof. The 
Wyoming plaster and those of Kansas, Texas, and Oklahoma, show 
nearly correct amount of water for properly calcined plasters as de- 
termined by the theoretical percentages. 

In some mills a few years ago and occasionally at the present time 
the plaster was drawn after the first settling. This method would 
enable the manufacturer to make plaster in a shorter period of time 
and so increase the capacity and lower the cost of fuel and labor. Such 
plasters have not been received with satisfaction by the trade. 

In a specimen of the Michigan plaster obtained from one of the mills, 
the water percentage after the first settling was 6.67 and at the close 
of the second settling was 5.70 per cent. This analysis would not con- 
demn the plaster in the first sample. It is similar to the amount in 
the Blue Rapids plaster of Kansas which is a standard grade of plaster. 
The second percentage agrees with the analyses given above of the 
Okarche, O. T„ and of the Quanah, Texas, plasters. The physical tests 
of these materials and their relations to the chemical analyses are 
discussed under that chapter. 

Prof. Bailey 3 has made an interesting series of analyses of the plaster 

1 Technology of Cement Plaster by Wilkinson, p. 6; 1897. 
» University Geol. Survey of Kansas, Vol. V, p. 166: 1899. 

ro. 2. 

No. 3. 

No. 4. 

No. 5. 

No. 6. 































158 GYPSUM. 

in Kansas in different stages of the manufacture, which are given be- 
low as taken from the Kansas report: 

No. J. No. 2. 

Silica and insoluble material 9.78 

Iron and alumnia oxides 0.30 

Lime sulphate 64.91 

Lime carbonate 6. 12 

Water 17.37 

Magnesium carbonate 0.70 

99 18 99.89 10112 98.77 96.76 99.35 

No. 1. Crude material. 

No. 2. Sample taken after two hours of boiling. 

No. 3. The finished material. 

No 4. A sample that has been set. 

No. 5. The screenings or tailings. 

No. 6. A sample that has been treated with a retarder. 

These analyses show that one-half the water is expelled in the first 
two hours, and about one-fourth in the last hour. The plaster as set 
(No. 4) shows about the original percentage of water as found in the 
uncalcined rock. The tailings or screenings (No. 5) are high in silica, 
the oxides of iron, alumina and magnesia, and low in lime sulphate with 
a water percentage about normal for the finished product. An analysis 
of the retarded plaster (No. 6) shows practically no chemical difference 
from the non-retarded plaster. The amount of retarder added is so 
small that it is not detected by analysis of the plaster. 

Michigan Finished Planters. 

The following analyses were made for the writer by Dr. F. B. Dains 
of Washburn College, except those of the Powers* Mill and the plaster 
of Paris made at the Alabastine Mill, which analyses were made in the 
chemical laboratory of the University of Kansas under the direction of 
Prof. E. H. 8. Bailey. 

Alabaster Plaster. 

Per cent. 

Silica and insoluble material 0.80 

Lime oxide (CaO) 38.95 

Sulphuric anhydride (S0 3 ) 54.07 

Water 5.24 

This analysis would give a probable composition by calculation of: 

Per cent. 

Silica 0.80 

Lime sulphate 92.95 

Lime carbonate 1 .26 

Wafer 5.24 


Ivory PUister of tlie English Mill 

Per cent. 

Silica and insoluble material 2.13 

Lime oxide (CaO) 36.89 

Sulphuric anhydride (S0 8 ) 52.19 

Oxide of iron (Fe 2 8 ) 0.36 

Water 8.55 


By calculation the analysis would give: 

Per cent. 

Silica 2.13 

Lime sulphate 88.71 

Lime carbonate 0.67 

Water 8.55 

Iron oxide 0.30 


Granite Plaster of the English Mill. 

Per cent. 

Silica and insoluble material 1.50 

Lime oxide (CaO) 37.23 

Sulphuric anhydride 52.10 

Oxide of iron trace 

Water 8.81 

By calculation: 

Per cent. 

Silica 1.50 

Lime sulphate 88.55 

Lime carbonate 1.43 

Water .' 8.81 

Iron oxide trace 

Plasticon Plaster of the Alabastine Mill. 

Per cent. 

Silica and insoluble material 1.60 

Lime oxide 38.29 

Sulphuric anhydride 50.1 1 

Loss, moisture, etc 9.20 


160 GYPSUM. 

By calculation: 

Per cent. 

Silica 1.60 

Lime sulphate 85.14 

Lime carbonate 5.84 

Water 6.63 

This sample showed traces of iron oxide and magnesia oxide. 

Alabastine Plaster of the Alabastine Mill. 

Per cent. 

Silica 1.38 

Lime sulphate 85.91 

Lime carbonate 4.48 

Water 7.48 

Iron and alumina 0.75 


Granite Plaster of the Powers' Mill. 

Per cent. 

Silica 8.64 

Lime sulphate 72.45 

Lime carbonate 7.96 

Water 4.94 

Iron and alumina 1.03 

Magnesium carbonate 4.98 


An examination of these analyses shows that the lime sulphate varies 
from 72.45 per cent in the Power's mill plaster to 92.95 per cent in the 
Alabaster plaster. The impurities vary from 22.6 to 2.06 per cent. The 
water percentage varies from 4.94 to 8.81 per cent. The loss of water 
in the calcining of these plasters is 74, 60, 55 per cent. 

These analyses compare favorably with those given of the French 
plasters and with those from other districts in this country. 
















§ 1. Introduction. 

The physical examination of a Portland cement is regarded as of much 
more practical value than the chemical analysis. Contracts are made on 
the basis of silcIi examination and all cements are carefully tested before 
being accepted for construction work, and the tests are carried along 
as the work progresses. There has grown out of this demand, a system 
of testing, 1 which is used with certain variations throughout the world, 
and is even a subject of legislative and governmental control. 

In the case of gypsum cement wall plasters such tests are seldom 
asked for by the trade, and they are not often made except by the manu- 
facturing companies themselves to secure a control over their product, 
so they may send out a uniform plaster. Such tests for scientific pur- 
poses have been made in this country by the University of Wyoming 
and by the Iowa Geological Survey. Before the results of either of these 
departments were published, the writer began work on the same lines 
and while the results have been partially outlined in the meetings of 
the Kansas Academy of Science, this is the first published account of 
the work. 

The growing use of plaster in construction, as ' ; staff' etc., will prob- 
ably lend importance to these tests in the future. 

Uniformity in results from cement tests and from gypsum plaster 
tests are difficult to secure and the personal error as well as the errors 
of manipulation are leading features in all such tests. Not only do tests 
on the same material by different persons vary, but even those made on. 
the same material by the same person show variations in results often 
impossible to explain. 

In testing hydraulic cements attempts have been made to establish 
standards for comparative purposes. This is seen in the work of the 
German Association of Cement Manufacturers, the French Government 
Commission in 1891, and in the conferences of the International Associa- 
tion for Testing Materials. In this country there have been no govern- 

I In tbe description of the methods of testing -cements, the author wishes to give due credit to the 
articles ofRL Humphrey in the Journal of Franklin Institute, as well as the various articles In the 
Proceedings of th» American Society of Civil Engineers. See also Mr. Humphrey's paper at the end 
of Volume VIII of these reports. 


162 GYPSUM. 

ment commissions appointed for this purpose, but in 1885 a committee 
appointed by the American Society of Civil Engineers reported on a 
set of rules for cement testing which have served as a standard for the 
work of testing cements in the U. S. In 1899 another committee was 
appointed by this society to revise these rules and bring them up to date. 
In my own work I have taken the rules of testing Portland cements 
and adapted them to use with the gypsum plasters. 

§ 2. Fineness. 

The fineness of grinding of cement is measured by the percentage of 
residue on No. 50, No. 100, No. 200, sieves having approximately 2,500, 
10,000, and 40,000 meshes per square inch. A good cement leaves prac- 
tically no residue on the No. 50 sieve; According to Humphrey, the 
sample should be thoroughly dried at a temperature of about 130° P. 
and the operation can be considered complete when not over 1-10 of 1 
per cent passes through after five minutes of continual shaking. 

While in Portland cements the fineness of grinding is one of the essen- 
tial parts of the manufacture, in gypsum plasters for ordinary uses, ex- 
ceptional fine grinding is not required and the extra cost of such grind- 
ing would not justify the work. Taking two plasters which are sold in 
the Kansas market, and they show the following variation in fineness: 

Per cent. 

Not passing through 20 mesh sieve 0.59 

Not passing through 40 mesh sieve 8.7 

Not passing through 60 mesh sieve 8.1 

Not passing through 80 mesh sieve 8.9 

Not passing through 100 mesh sieve 15.1 

Through 100 mesh sieve 57.4 

Lost in sieves 1.21 


Per cent. 

Not passing through 20 mesh sieve 0.48 

Not passing through 40 mesh sieve 5.35 

Not passing through 00 mesh sieve 2.21 

Not passing through 80 mesh sieve 2.83 

Not passing through 100 mesh sieve 3.41 

Through 100 mesh sieve 84.56 

Lost in sieves 1.16 


§ 3. Weight. 

According to Michaelis a good Portland cement should not weigh over 
75 pounds per cubic foot. The specific gravity runs from 2.72 to 3.05. 
The gypsum rock runs about 2.3 and the calcined plaster has a specific 


gravity of 1.81. A cubic foot of plaster of Paris weighs 54.76 pounds 
determined on Grand Rapids plaster. When set it weighs 103.3 pounds, 
and with two parts sand to one part plaster a cubic foot weighed 126.2 

§ 4. Gauging of Plaster. 

The preceding tests are applied to the dry material, other tests 
usually looked upon as more important are applied to the cement or 
plaster mixed with water. The amount of water used in the mixtures 
is important in all comparative examinations. 

Briquettes made from different proportions of water are found to vary 
in the tests made. It is then important to determine the percentage 
of water necessary to make the pats and briquettes of plaster of just 
the proper consistency for manipulation. The proper mixture has been 
termed the "normal consistency'- of a cement. In many laboratories great 
care is taken to determine this amount of water. 

"At the Charlottenburg testing laboratory in Germany it is the prac- 
tice to determine the percentage of water to be used, by mixing the 
cement to a'syrupy paste so that it will run from a knife (6 by iy% inches) 
in long thin threads without forming lumps. Representing the quantity 
of the water for this condition by N, then the percentage of water (W) 
required to produce a normal consistency is obtained from the formula 
w = — ti- for neat tests and w = — ^— for sand tests (1 to 3)" (Hum- 
phrey. ) 

A simple method is also given by Humphrey which he states gives 
results closely agreeing with the preceding. This consisted of moulding 
the plaster in a ball and dropping it from a height of one foot. The ball 
is of the proper consistency when it does not flatten materially or crack 
in this experiment. 

In the present work on gypsum plasters different proportions of water 
were used until a normal consistency was determined, which would 
thoroughly moisten the plaster and, on striking with a trowel, would 
show a moist surface but not bring water to the surface. Different 
brands of plaster required slightly different percentages of water. In 
the earth plasters 30 per cent of water represented the average amount 
to be used, while in the plasters made from the rock, 40 per cent was re- 
quired. For sand mixtures of earth plaster, 13.4 per cent of water was 

§ 5. Time of Setting. 

The time of the beginning of set and the time of final set in cement 
and plaster give a classification into rapid and slow setting. Ordinary 
plaster of Paris sets in a few minutes but by the addition of a retarder 
the set may be delayed two hours or even twenty-four hours. 

164 GYPSUM. 

The fact that some gypsum plasters run uneven in the time of set is 
considered by the practical plasterers as an argument against them. 
The workman uses one day a plaster of certain make which sets as a 
fairly slow plaster and if the next lot of plaster has a quicker set, he has 
trouble with the wall unless he uses considerable caution. Certain 
brands run remarkably uniform in time of setting and stand in high 
favor with the trade. The cause of this variation is not usually sought 
for by the manufacturer. The careful chemical examination employed 
in all Portland cement mills, is seldom made in gypsum mills. The 
material is placed in the kettles, burned so long, and a certain amount 
of retarder added, and the finished product is ready for the market. In 
gypsum rock quarries the quality is usually uniform, but in many of 
ii the earth deposits the variations are marked, and careful manipulation 

is necessary to send out uniform plasters. 
- The setting time of gypsum plaster may be determined in the same 

! Wiiyas in cements. The Vicat needle which carries a given constant 

weight is brought against the surface of the properly gauged pat of 
cement or plaster. When this needle under a load of 50 grams failed to 
sink half way into the pat, the initial set is said to have commenced. 
When under a load of 300 grams, it fails to sink into the mass the final 
set is. said to have taken place. This method of determination is in 
common use in the cement laboratories of England and also in this 

This apparatus, illustrated in Fig. 42, consists of a frame K, bear- 
ing the movable rod L, having the cap A at one end, and the piston 
11, having a circular cross-section of 1 centimeter diameter at the other. 
Th£ screw F holds the needle in any desired position. The rod carries 
an indicator which moves over a scale (graduated to centimeters) at- 
tached to the frame K. The rod with the piston and cap weighs 300 
grams; the paste is held by a conical hard rubber ring, I, 7 centimeters 
in diameter at base, 4 centimeters high, resting on the glass plate J. 15 
centimeters square. 

A convenient method with apparatus readily made in any laboratory 
is by the Gihuore wires. A wire with a llat area of one-twelfth inch and 
loaded with one-fourth pound is used to determine the initial set. This 
needle fails to penetrate the plaster when the set has commenced'. A 
second wire with one-twenty-fourth inch area and loaded with one pound 
will not penetrate the mass when the final set has taken place. These 
wires were prepared as described and placed in a wooden frame so as to 
keep them vertical and give a direct pressure on the pat of plaster. 

The tests were made on neat cement plaster and carefully timed, 

the wires were kept clean of all adhering plaster. The time of initial 

• set was determined within .,a range of very small variation, but the 

final set was not so readilv determined as it is difficult to determine the 


exact time of the needle making no impression. In the mixing of gyp- 
sum plaster with water it is very difficult to get it thoroughly mixed 
especially in quick setting plasters, and as a result portions of the pat 
will be set while other portions are still soft. This result may possibly 
be explained by inequality in the distribution of the retarder or by 
some portions of the plaster being more highly calcined than other parts. 
In the results of these tests average times of set were selected from a 
series of tests. 

Initial set. Pinal set. 

Pure plaster of Paris 7 min. 20 min. 

Roman plaster 25 " 3± hours (retarded. ) 

O. K. plaster 50 " 4 

§ 6. Tensile Strength. 

The most popular series of tests on cements are those determining 
the tensile strength as these are regarded as easy to make and not re- 
quiring very expensive apparatus. 


In the early days of cement testing, two machines were used, one 
known as the Grant machine now represented by the Riehle and Olsen 
machines which are long simple lever machines. The other type smaller 
and more compact, the Michaelis testing machine, is now found in a modi- 
fled form in the Fairbanks testing machine. The later machine is per- 
haps the more popular in this country on account of the ease of handling 
and compactness, and was used in all the experiments in our laboratory. 1 

The briquettes of cement or plaster are moulded in single or gangue 
moulds which are held together by clamps in the middle or at the ends 
of the moulds. They are usually made of brass. The shape of the mould 
has been modified from time to time, and slightly different forms are 
now used in different parts of the world. The original square mould of 
the Grant machine had a one and one-half inch section, but was modified 
later by Grant so as to have angular ends and this form is still used in 
England. In the Michaelis machine the briquettes were rounded at the 
ends and at the center were slight indentations or cunettes to insure the 
briquette breaking at the center. This form is the standard in Germany 
and France and has a cross section at the center of five square centi- 

In the United States the briquettes have slightly angular ends and 
taper toward the center where the cross section is one inch. Unless* 
the briquettes are carefully adjusted, cross strains are set up and the 
briquettes tend to break in other places than the center. In the earlier 
machines the clips of the machine closed tightly on the briquette, allow- 

1 See VoL VIII, Part 3, of these reports for figures of the different testing machines, also Fig. 40. 



ing no room for adjustment. Modern clips are larger and touch the 
briquette along four lines only, and so are more readily adjusted to 
remove anv cross strains. 

Fig. 36. 

Fig. 37. 

Fig. 38. 

Fig. 39. 

Fig. 3A. Cement Briquette and Clip, used in England. 

Fig. 37. Cement Briquette and Clip, used in United States. 

Fig. 38. Cement Briquette and Clip, used in United States. 

Fig. 39. Cement Briquette and Clip, used in Germany and France. 


The cement or plaster is thoroughly mixed or gauged with the proper 
amount of water, on a non-absorbing surface like plate glass or marble. 
The German method is to mix a slow setting cement three minutes and 
a quick setting cement one minute. Plaster being usually quick setting 
should be mixed as quickly as possible. Mechanical mixing machines 
like the Russell jig and Faija mixer are not used in very many Ameri- 
can laboratories. The work is carried on in a room of uniform tempera- 
ture if possible. 

When the plaster is thoroughly mixed it is pressed into the mould by 
hand and gently forced into place. The surface is then struck off smooth 
with the trowel and mould turned over and the other side smoothed off 
if necessary. After a few hours the briquettes can be removed and 
after being carefully numbered are laid aside for the breaking tests. 

In the experiments of the Washburn College laboratory, with quick 
setting plasters, one briquette was moulded at a time, using 3 Vif ounces 
(99.2 grams) and 40 cc. of water representing the 40 per cent mixture. 
In the slow setting plasters 19 ounces (538.4G grams) are used with 


about 165 cc. of water and five briquettes are made, a 30 per cent mix- 
ture. The proportion of water varied somewhat with the plaster used 
in the experiments. In the Kansas plasters for a stiff mixture, the water 
percentage varied from 26.3 per cent to 40 per cent for neat briquettes 
(without sand); and in sand mixtures (2 to 1) the water percentage varied 
from 12 to 14, and proportions were about the same in the Michigan 
plasters. Nearly 600 briquettes were made and broken at intervals of 
24 hours, 7 days, 30 days, 6 months, and 1 year. 

The briquettes for the long time test were set on edge on glass and 
kept in a room of fairly uniform temperature until broken. The sand 
used was ordinary Kansas river sand screened through a sieve (No. 20) 
of 400 meshes and held by a screen (No. 40) of 1,600 mesh, and carefully 
dried. The sand mixtures were two parts of sand to one of plaster. 
The quick setting plasters required the higher water percentage in mix- 
ing and the slow setting, the lower percentage. 

Fig. 40. Fairbanks testing machine. 


The briquettes were broken in a Fairbanks machine. In this portion 
of the work care must be taken to properly center the briquettes and 
avoid cross strains with resulting cross breaks away from the center 
The presence of air bubbles and incipient cracks will sometimes cause 
the diagonal breaks even in the most careful manipulation. In the 
briquettes of high strength the bucket was always loaded with a light 
weight and the shot allowed to flow in a small and uniform stream. 

• tiJ* 




Geological Survey of Michigan. 

Vol. IX Part II Plate XXI. 





The tests of the Michigan plasters were made in the laboratory under 
my supervision by two advanced students, Mr. Elmer Schultz and Mr. 
John Worsley, and their results were accepted as thesis work for their 
degrees, by Washburn College. 


Kind of plaster. 

24 hours. 

One week. 

One month. 



































Roman (Kansas). Neat { W2 

I 298 

f IM 

Roman (Kansas). Two parts sand -; L£ 



O. K. {Oklahoma). Neat \ 


O. K. (Oklahoma). Two parts sand. .. 

Keene's Cement (Kansas). Neat. 

Keene's Cement (Kansas). Two parts ! 
sand J , 

Satin Spar (Kansas). Plaster of Paris. I 
Neat { 

Crystal Rock (Kansas). Two parts 













































► 558 


► 525 

► 410 



► 595 






















One year. 







390 j { 4U 

494 I f "' 

469 'j 









380 1 

362 [ 

405 ; ! 

399 ! 




Geological Survey of Michigan. 

Vol. IX Part II Plate XXI. 






\ t 



* rr * v 

J - t 






* n 




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H . /j ) 



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,r . 



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u i 


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\ n^ 


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7 v 


i j A* 


*l hi 





'i « n 


i»»* ■_■;, 


^r Attn 






Kind of plaster. 

A. Made at Grand Rapids. Neat . 

A. Same plaster. Two parts sand. 

R Made at Grand Rapids. Neat. 

C. Made at Grand Rapids. 

C. Same plaster. Two parts sand. 

D. Made at Grand Rapids Neat 

D. Same plaster. Two parts sund. 

* Three months, 
f Two months. 

24 hours. One week .One month. : Six months. 


215 | 
215 : . 

200 r 
238 | : 

106 i 


i : 99 





»« | J 

117 jj 




I 125 






49* : 

387 ! 
320 I 


< & 








3 S 

o > 

3 » 

2 ! < 





.... 405 

...i 445 

....; 390 

...J 403 


: 210 

302 , 
295 ' 

J500 gjj , , 441 
319 i 


♦555 ! 



■ ♦6W 




350 jj 

207 I i 


♦353 , 
♦321 ' 

+503 : 

I- 680 

\ 328 



v - J 1-302 | 


311 I i 

410 ^ 
261 . 
359 ; ' 





One month. 




Kind of plaster. 






























■ 277 

O. K, (Oklahoma). One year old plaster. Neat ., ,„.,. ...... 





ftnnmn {fviin,s.ASJ * }q£ J^ftrolfl plftStftr NCIIj. --- 




[ 337 








pH3 1 

Plaster of Parts. (Kansas), One year old plaster. Heat. •. 









RomttQ (Kansas^ One year old piaster. Two parts sand ..»»-.? 


Discussion of Results. 

In the gypsum earth plasters of Kansas the maximum strength ap- 
pears to be reached in one month and then they decline in six months 
and one year. This decline is more marked in the neat plaster than in 
the sanded plaster. These plasters are represented in table I by the 
Roman and O. K. 

The rock plasters represented by Keenes and Satin Spar show their 
greatest strength in six months. The Crystal Rock also a rock plaster 
gave its greatest strength in one week. The greatest strength recorded 
was of plaster of Paris in six months when one briquette broke at 786 
pounds. In sanded mixtures the rock plaster stood, higher tests than 
the earth plasters. 

Even a hasty examination of these tables shows the variation in re- 
sults of the same plaster tested in the same length of time by the same 
person who endeavored to secure as uniform manipulation as possible. 
It has been urged by some of the practical operators that only the high- 
est tests should be used in judging plaster or cement, because the plaster 
will have a certain highest strength which cannot be increased by the 
person making the test, but which can be lowered, and in the mixing 
of the plaster the workman is more apt to lower the strength than to 
increase it. The results, however, as given will probably agree more 
closely with the average results of the plasterer in his work, who will not 
always if ever secure this greatest strength of the plaster. 


/ AAiPnt % 


flue Ifetfc 






j,***i], m ^ 




f £ 

•V * 


\ ' '' 

""*!» ^ r 




*"t, r 


/ /lil 

i 1 

* / 

jifmv ft- *4 0< 

t3 ^x 



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W* »l 

* >* 


. .-v V t 






^ "*« 


f / ' 






f * 
1 ' 
/ ' 

/ i 

/ > 



f ** / 

/ ' 

f t 



-" , t 


: / t 
: / ' 
■ / / 




/ * 

/ ? 


\«-" <* 






Fig. 41. ('hurt of tensile strength of gypsum plasters, one day. one week, 
one month, six months and a year, after setting. 

1. O. K Cement Wall Plaster (neat). 

2. O. K. Cement Wall Plaster it parts sand). 

3. Roman Cement Wall Plaster (neat). 

4. Roman Cement Wall Plaster (S parts sand). 

ft. Crystal rock Cement Wall Plaster (S parts sand). 

0. Satin spar Cement Wall Plaster (neat). 

7. Keenes Cement Plaster (neat). 

8. Keenes Cement Plaster (3 pans sand). 

172 GYPSUM. 

It must be clearly kept in mind that the lowest of these tensile 
strengths is far greater than any strain that will ever be applied to a 
wall. So in practical work these are all good plasters, and the ease of 
working, and the uniform results of different ton lots will be of more value 
in determining the superiority of one brand over another. Such tests 
as are given in these tables are valuable for comparative purposes. 
• Why the strength should fall after one or six months is an unsettled 
problem. The amount of relarder added is so small that we can hardly 
look to that for an explanation, though it may have some effect on the 
crystal network and changes in the retarder in time may effect the 
strength of this network. The real explanation lies hidden in the adjust- 
ment of crystals in the network and belongs to the obscure subject of 
crystallization, its causes and steps in its progress. It is evident that 
in some of these plasters the early changes in crystal formation are 
slower than in others as a marked variation is seen in 24 hours which 
disappears later. This is especially true of the sanded plasters. 

The Michigan plasters are all made from rock, as no gypsum earth 
deposits are known in the state. The greatest increase in strength 
of these plasters from 24 hours to one month as is also true of the 
Kansas plasters, shows that the final set as determined by the needles 
does not represent the complete setting of the plaster. The changes of 
crystallization which we call the set are going along rapidly at first then 
more slowly for one month and in some cases six months, and the re- 
adjustment of the network of crystals would seem in some of these 
plasters to be going on for a year after they are mixed with the water. 

A number of the Michigan plasters seem to reach their maximum 
strength in one week and decline in strength in one month. The greatest 
strength recorded was of a briquette broken at 73G pounds after three 
months. These results of tests do not show any great variations from 
the same kinds of Kansas plasters. 

Tests on Old Plasters. 

The statement is often made that gypsum plasters cannot be kept 
long without losing their strength and that in a few months they are 
of low strength or even worthless. Several sacks of plaster were left 
in a room near the laboratory for over a year. These sacks were open 
and the room was damp in the spring, and not heated in the wintef, 
so the plasters were exposed to a varying temperature from the hot 
summer to the cold winter. Briquettes were made from these samples 
and broken giving the results shown in table III. These plasters were 
from the same sacks which furnished the material used for "the bri- 
quettes shown in table I. 

Comparing the results of the two tables, of fresh plaster and plaster 


exposed one year, it is found that the O. K. plaster in 5 months has de- 
creased in strength from near 543 pounds to 458. The plaster of Paris in 
one month from 595 to 536 pounds. The Roman in one month from 553 to 
337, and in five months from near 430 to 150 pounds. This last brand is 
the only one which shows any serious effect of the exposure. These plas- 
ters under as bad conditions of exposure as would ordinarily be found 
show decrease of strength, but they are still after one year's exposure 
good plasters. 

To test frost effects on these gypsum plasters, a number of briquettes 
were made and as soon as set were placed out of doors in the open air 
for one week with the temperature below freezing, and the briquettes 
broke from 352 to 793 pounds with an average of 500 pounds, showing 
practically no effect on the strength for that time. 

Soine Low Tests. 

At some of the mills there is a tendency to draw the plaster from 
the kettles before the second boiling, and some of the operators have 
claimed that such plaster is just as good as any other. If this claim was 
true it would give the advantage of calcining plaster with less fuel and 
save much time so adding to the capacity of the plant. Among the 
various sacks of plaster brought from Michigan, two sacks were tested, 
one of which showed by chemical analysis a high percentage of water 
and evidently it had been drawn from the kettle too soon. The plaster 
when set would break when taking it from the mould and would not 
test as high as 100 pounds when the greatest care was taken with the 

The other brand showed too low a water percentage and the tests 
showed it had a very low tensile strength. It was tested neat and after 
60 days gave the following results: 

91 pounds 
150 pounds 
101 pounds 

232 pounds Average 150 pounds. 

186 pounds 
145 pounds 
139 pounds 

Another sack of good plaster from the same mill made at another time 
gave, when tested in the same way and after the same length of time: 

503 pounds 

«8 P pZ£ Am*.**™*. 

312 pounds 

These results seem to show that of the two evils, under-burning and 
over-burning, the former is the greater. These plasters should reach in 

174 GYPSUM. 

60 days at least 500 pounds tensile strength, as they are made from 
good rock and with good appliances for calcining. These tests are use- 
ful in showing that poor plaster can be made from the best material 
by faulty manipulation. It may be due to cheap and inexperienced cal- 
ciners or to careless ones. This trouble is found in all plaster fields 
and I have found similar poor plasters in other districts. The tests 
were carried out with plasters from nearly all the Michigan mills, and 
these two sacks were the only poor plasters found, and further, the mills 
that made these poor plasters are sending out some of the finest grades 
of Michigan plaster. 

§ 7. Comparison of Physical Tests with Chemical Analyses. 

It was thought that a careful comparison of physical tests with the 
chemical analysis might throw some light on the effects of certain in* 
gredients in the rock on the strength of the plaster made from the rock. 
Wh?n the results of these tests are compared, a variation is found in the 
tests on plasters at different mills made from rock of practically the 
same chemical composition. The time of calcining and the amount of 
heat used as well as many other factors vary and so produce variations 
in results which obscure the effects of the rock impurities. 

The eartli plasters with their impurities of clay, silica, and lime, set 
slower than the rock plasters and usually show a little lower tensile 
strength, especially when mixed with sand. 

Another method was used to determine the effects of these impurities. 
Pure plaster of Paris was tested and then varying proportions of pow- 
dered limestone were added, also different proportions of powdered clay. 
Briquettes were made from these mixtures and broken after 30 days. 

Carbonate of lime 

Pure plaster of 

r cent of 


Per cent 

Clay mixture. 





of clay. 



Lbs. Averai 
585 > 


392 V 

275 ) 





534 [ 595 
667 ) 


248 £ 









348 } 




494 i 




321 J 
332 ) 






389 ( 











285 J 







The addition of the lime and clay had a tendency to cause the briquettes 
to swell and so make them difficult to place in the clips of the machine. 
This binding of the briquettes causes them to break away from the 
center in a number of cases. The addition of these impurities lowered 
the strength, but the different proportions did not change the results 
materially until the 10 per cent mixture was reached. The setting time 
was but little altered. 

Another line of experimental work was tried by mixing the ground 
clay with ground gypsum rock and calcining the mixture as follows: 
One pound of ground clay was mixed with seven pounds of gypsum flour 
and placed in a kettle heated to 250° F. (120° 0.) and heated for a half 
hour to a temperature of 266° F. (130° C.) when the boiling ceased. The 
mixture was heated 15 minutes longer and the temperature reached 386° 
F. (196° C.) and then the whole mixture was withdrawn having been 
heated about one hour. The color of the finished plaster was reddish. 
It set in one hour and the briquettes in one week had a tensile strength 
of 500 to 585 pounds. A one-fourth mixture gave a reddish plaster 
which set in one and one-half hours. 

The adding of the clay impurity before calcining the rock increased 
the tensile strength and formed a slow setting plaster. In sand mix- 
tures, however, the plaster showed a very low tensile strength similar 
to the Keene's cement tests as given in table I in an earlier part of this 
chapter. Such cements are used neat or if mixed with sand have lime 
added to them. The specifications with the use of Keene's cement state 
as imperative that for sand mixtures three bushels of slaked lime must 
be added for each 100 square yards of surface. The tests given were on 
the cement without any addition of lime. 

The analysis of the mixture of one part of clay to seven parts of 
gypsum after calcining is given below with analysis of plaster made 
from gypsum rock and gypsum earth. 

Mixture Earth Rock 

7 to 1. Plaster. Plaster. 

Silica and insoluble material 12 30 12.02 1 .20 

Iron and alumina 0.78 0.44 0.20 

Lime carbonate 0.07 14.39 1.68 

Lime sulphate 83.48 68.36 89.42 

Water 2.80 4.98 6.82 

99.43 100.19 99.32 

The mixture agrees closely with the earth plaster in its percentage 
of silica, but is lower in lime carbonate. In percentage of lime sulphate 
the mixture stands between the earth and rock plasters. It was evi- 
dently burned at a higher temperature than the other plasters as shown 
in the water percentage, but the high strength of the plaster would 
argue against this percentage of water being a defect in the plaster. 



The clay when added to the calcined plaster has little effect, but when 
added before calcining it has the effect of a retarder without lowering 
the strength of the plaster. The experiments would suggest that the 
clay in the earth plaster acts as a retarder, but that the full effect of 
this impurity is only seen when the plaster is heated to a high tempera- 

§ 8. Compression Tests. 

Compression tests on cement are also held in high favor by many ex- 
perts. On account of the expense of the machinery for this work and the 
difficulties in making the tests, the compression tests are not often 
made. They are usually made on two inch cubes. Such tests have been 
made on gypsum plasters by the Wyoming Geological Survey. 

A series of compression tests were made with the same mixtures and 
the same time of exposure as in the tensile tests. The plasters used 
were mainly Kansas products and they were moulded in prisms of the 
size 2 by 2 by 4 inches, and the pressure was applied to the ends of the 
prisms in a hydraulic compression machine at the Sante F6 shops at 
Topeka. The results are given below: 

One week. One month. Six months. 

Plaster. Lbs. A v. Lbs. A v. Lbs. Av. 

Roman 7600) 7250) 11050) 

Neat 7850- 7583 7400* 7550 9450^ 9440 

7300 ) 8000 ) 7820 ) 

Roman 5200) 4100) 4950) 

Two parts 5000 [ 4733 4KXH 4833 4720^ 5143 

sand 4000) 6300 ) 5760) 

v J5' -1SS1 l4 -*>°] l000 °] 

j£™ 1 7300 12475 \ 12966 11830 [ 10926 

§SoJ lll75 i 10950 j 

'' ?;L rt , 5^1 *00 1 4700] 

Two parts , 25 | ;125 ^ - 916 ^ I 575Q 

7125 1 7550 J fi050 | 

Crystal Rock 8000 ) - mn 7830 ) r - n 

Neat 6000 f <00 ° 5350 f 6 ' )J0 

The next table shows the relation of the compression tests per square 
inch to the tensile strength per square inch, being as many times the 
tensile strength as is indicated by the figures. 

Plaster. One week. One month. Six months. 

Roman, neat 4.8 3.2 5.5 

Roman, two parts sand 3.3 3.2 3.5 

O. K., neat 7.9 6.1 5.0 

O. K., two parts sand 19.5 4.1 3.1 

§ 0. Absorption Tests and Effect on Strength. 

Briquet tos of gypsum plaster were made in the moulds and after dry- 

Geological Survey of Michigan. 

Vol. IX Part* II Plate XXII. 




ing were placed in water, then in air and allowed to dry, and then placed 
again in the water, and after drying were broken. 

Three briquettes of neat O. K. plaster made in Oklahoma showed an 
average weight after 24 hours in the air of 118.6 grams. These were 
placed in water for 72 hours and gained 4.8 grams in weight or a gain 
of 4 per cent. This does not represent the real gain of water by absorp- 
tion, as part of the material of the briquette went into solution, as 
shown by their weight after exposure in the air of the same room for 
a week, w r hen they showed an average weight of 112.6 grams, which 
compared with their weight when removed from the water (123.39 
grams) shows a gain through absorbed water of 10.79 grams or 9.5 
per cent. These briquettes were again placed in water for 60 hours, 
then left in the air for 12 days. They w r ere broken 32 days from the 
time of mixing and showed a maximum tensile strength of 522 pounds 
and an average of 466 pounds. The same cement tested in the ordinary 
way in 30 days gave a maximum strength of 594 pounds with an average 
of 525 pounds. 

Roman cement plaster made in Kansas was tried in the same way. 
The neat briquettes had an average weight of 111.14 grams and after 
three days in the water showed an average weight of 118.1 grams, or 
a gain of 6.96 grams or 6.2 per cent. These were then exposed in air 
for five days and placed in water six and one-half days and left in the 
open air again fourteen days. Thirty days after the first mixing the 
briquettes were broken and showed a maximum strength of 587 pounds 
and an average of 496 pounds. The Roman plaster treated in the ordi- 
nary way showed a maximum of 567 pounds and an average of 553 

Keene's cement plaster made as a special preparation of hard plaster 
with an average weight of briquettes of 123 grams, after three days in 
water weighed 129.6 grams, or a gain of (y,(i grams or 5.1 per cent, and 
treated in the same way as the Roman gave a maximum test of 465 
pounds and an average of 445 pounds. Tested in the ordinary way the 
maximum tensile strength was 517 pounds and average was 423 pounds. 

The loss in strength shown in O. K. plaster in this treatment was 59 
pounds; in Roman, 57 pounds; while in the special brand of Keened 
cement, an increase was shown, probably due to some error in manipula- 
tion of the tests. These water tests show that standard gypsum plasters 
are not injured to any great extent by such soaking. This accords with 
practical experience for often gypsum plaster walls wet from leaking 
roofs dry out and appear to be as strong as ever. 

§ 10. Tensile Strength of Gypsum Plasters and Lime Plasters. 
An effort was made to secure the tensile strength of ordinary lime 
plaster moulded in Fairbanks moulds and broken in the testing machine. 


One week. 

One month. 

Six months. 

Lbs. Av. 



Lbs. A^ 


Hi 19 

18 j 





38 1 . fi 

178 GYPSUM. 

The lime was carefully slaked and mixed with two parts of sand. The 
briquettes so made showed a tendency to crack and many of the experi- 
ments were failures on this account. 


Lime plaster fj| | 1Q SJ I *7 42 I 50 

Two parts sand. 1(i ' 19 -* > Zi "° ' ™ ■ 

These results show a very low tensile strength for the lime when 
used in these small masses. The addition of hair to the lime as is done 
in the ordinary use of lime plaster and the larger quantities give better 
results, than would be indicated by these tests.* Lime plaster has a. 
good tensile strength on the wall, but cannot equal the hard gypsum 
plasters. The effect of dampness, jars, fire, etc., are much more destruc- 
tive to lime walls than to gypsum plaster walls. The durability of the 
gypsum plaster wall is certainly much greater than is the case of +* 
lime wall. The tensile strength of gypsum plaster walls can be incr 
by the addition of fibre and especially by the use of wood fibre. 1 . 
the intention to make a series of tests of such fibred plasters, but it is 
difficult to secure uniform results with ordinary fibred plasters when 
used in small space of a briquette mould as the fibres are long enough 
to get in the way and leave air bubbles in the plaster. I was unable 
at the time these tests were made to secure samples of wood fibred 
plaster. In these plasters the wood fibre is small and would not cause 
the same trouble in the work that the longer fibre did. 

§ 11. Adhesion Tests. 

Adhesion tests have been made at times on Portland cements, but 
they are not common. It is found that such cement will adhere to 
ground glass better than to brick or stone and adheres but poorly to a 
wood surface. A convenient method of applying the test is to cement 
two stones or bricks crosswise at right angles and determine the weight 
necessary to pull them apart. 1 

In tests of gypsum plasters made by the Iowa Survey, pieces of paving 
brick were ground on an emery wheel so as to give approximately one 
inch cubes. One face of the cube was carefully ground to give a cross 
section on one square inch. These pieces were placed in cement moulds 
with the true one inch surface at the center of the mould. The other 
half of the mould was filled with plaster and the vacant place around 
the piece of brick was filled with neat Portland cement mortar. When 
these briquettes were broken they showed the adhesive strength of the 
plaster to be only a fraction of the tensile strength. 

1 See article on cement tests. Vol. IX, Purt III, of these reports. 


In the present work a considerable number of adhesion tests were 
made by selecting briquettes which had been broken at the center and 
were fairly smooth in section. These were thoroughly wet with water 
and placed in the moulds and the remaining half was filled with plaster. 
The results of these tests while perhaps not valuable for scientific com- 
parisons with tests made in other laboratories by different methods, yet 
throw light on the adhesive character of gypsum plasters when spread 
over walls with another coat partially dry, or in repair work on old 
walls. When the old plaster in these experiments was not wet, there 
was scarcely any trace of adhesion, which shows that in such repair 
work the wall should be thoroughly wet before the new plaster is added. 

This method used on the Iowa Survey gave adhesion tests which sel- 
dom reached 100 pounds in four weeks and most of the tests showed less 
than 50 pounds. The method used in the present work showed higher 
results, and results that were in the main no more variable than in 
tensile tests. 



Two parts 

One day. 
Lbs. Av. 


49 [ 48 


69 J 


37 1 
45 f 


One week. 
Lbs. Av. 


One month. 




36 ( 


133 ) 



Two months. 
Lbs. Av. 


106 c 
167 I 
146 I 
318 J 


Three months. 
Lbs. Av. 

247 J 

> 273 



195 ) 


The relation of the adhesive strength to the tensile is shown in the fol- 
lowing table, the tensile strength being as many the adhesive as is in- 
dicated by the figures. The three months adhesive tests arc compared 
with the six months tensile tests. 


One day. 

Oae week. 

Oae month. 

Three months 

to six m >nths 





Not deter- 


Two parts 





§ 12. Specific Gravity. 

No tests were made *for the determination of the specific gravity of 
these plasters. Experiments could be made along this line which would 



without doubt produce interesting results. It was hoped -earlier in the 
work that opportunity would be found to make these determinations. 
According to Humphrey, LeChatelier's method is the most convenient 
to use in determining the specific gravity of cements, and it could well 
be used with the gypsum plasters, and his description is here given. 

The apparatus consists of a flask D of 120 cc. capacity (see Fig. 42), 
the neck of which is about 20 centimeters long. In the middle of this 
neck is a bulb C, above and below which are two marks engraved on 
the neck, the volume between these marks E and F being exactly 20 cc. 
Above the bulb the neck is graduated into one-tenth cc. The neck has 
a diameter of nine mm. Benzine free from water and being neither very 
volatile nor hygroscopic is used in making the determinations. 

Fio. 4*2. Modern form of Vicat needle and other testing apparatus for Portland Cement. 
Upper row left to right, Vicat needles, (iilmore wires, specific gravity apparatus. 
Xiower row, moulds, graduate, sieves. 

The specific gravity can be determined in two ways: 
1. The flask is filled with benzine to the lower mark E, and G4 grams 
of powder are weighed out and carefully introduced into the flask by 
the aid of the funnel B. The stem of this fuunel descends into the neck 
of the flask to a point a short distance below the upper mark. The 
cement cannot stick to the sides of the neck and obstruct the passage. 
As the level of the benzine approaches the upper mark, the powder is 
introduced carefully and in small quantities at a time, until the upper 
mark is reached. The differences between the weight of the cement 


remaining and the weight of the original quantity (64 grams) is the 
volume which has displaced 20 cc. of the liquid. 

2. The whole quantity of the cement is introduced and the level of 
the benzine rises to some division of the graduated neck. The reading 
plus 20 cc. is the volume displaced by 64 grams of cement. 

The specific gravity is then obtained from the formula : 

a <c •*_ weight in air 

Specific gravity = -r-. — i- 5 — = —r-: 

° * displaced weight 


loss of weight in liquid. 

During the operation the flask is kept immersed in water in a jar A, 
in order to avoid any possible error due to variation in the temperature 
of the benzine. The cement in falling through the long neck completely 
frees itself from all air bubbles. The results are said to agree within .02. 

§ 13. Influence of Sand on Plaster. 

The addition of sand lowers the tensile strength of the plaster as is 
shown in the tables of the tests already given. In ordinary lime plasters 
sand is necessary to increase the adhesive properties of the plaster, and 
sand is said to increase the adhesion of Portland cements. In the gypsuin 
plasters, the tests of adhesion given show that the addition of sand de- 
creases the adhesion of plaster as well as the tensile strength. These re- 
sults would indicate that sand is not needed in gypsum plasters to give 
them tensile or adhesive strength. The addition of sand to these plasters 
makes them cheaper as a sack of plaster with the addition of the proper 
amount of sand will cover a greater surface, and without injuring the 
strength in any practical degree. 

Another important influence on the addition of the sand is in making 
the plaster easier to work. Pure gypsum plaster mixed with water is 
more or less sticky and tends to roll up into lumps. The addition of 
sand overcomes this trouble. The advantages of sand mixtures are not 
in the strength and probably not in the duration of the wall, -but rather 
in convenience to the workman, and therefore in the better character of 
the wall for this same reason, and in the reduction of the cost. This 
latter reason sometimes tempts the workman to add an excess of sand 
and so to make a weaker wall. Crumbling gypsum plaster walls that are 
sometimes reported are either due to improper burning, or to too much 
sand added, or again to use of old partially set plaster left in the mortar 


§ 1. Deposition by Action of Sulphur Springs and Volcanic Agencies. 

Various theories have been advanced to explain the origin of gypsum 
in various parts of the world. In order to arrive at a satisfactory ex- 
planation of the origin of the gypsum deposits of Michigan, a brief resumfe 
of these theories will be given in this chapter. 1 

Gypsum is deposited directly by some thermal springs as in Iceland 1 , 
where it is formed by the decomposition of volcanic tufa by acids dis- 
solved in water. The sulphurous acids become oxidized to sulphuric, and 
thus convert the carbonates, especially of the lime and magnesia, into sul- 
phates. Through evaporation the sulphate of lime is deposited, forming 
layers of fibrous and selenitic gypsum. 

Small gypsum deposits are found around the fumaroles 2 of the craters 
and lava streams in Hawaii where sulphurous acid is converted into 
sulphuric, and attacks rocks which contain lime. Gypsum is found in the 
form of acicular crystals associated with sulphur in the craters in New 
South Wales.* The gypsum concretions of the Hartz are regarded as due 
to the action of sulphur vapors on lime rock. According to Lapparent 4 
the large deposits of gypsum and anhydrite at Montiers, Bourg-Saint- 
Maurice, in the western Alps and Switzerland are due to the transforma- 
tion of lime through sulphur reaction. 

Dana' explains the origin of a portion of the New York gypsum as a 
secondary mineral due to the alteration of the limestone by action of 
sulphuric acid. The acid comes from sulphur springs by the oxidation of 
the sulphuretted hydrogen. Such springs are found in New York espe- 
cially near Salina, and Syracuse, also at Byron in Genesee County. The 
layers of shale sometimes pass through the gypsum, and the gypsum is 
connected with the overlying w r at(?rlime beds as shown in Figure 43 after 
Hall taken from Dana's text book. 

1 See also Vol. V. of these reports, the introduction to Part 2. 
i Bunsen in Annalen der Chem. 1847 

• IowaGeol. Survey, Vol. XI£. p. 116: 1902. 

3 Minerals or New South Wales, p. 164: 1888. 

* Lapparent Geologic p. 1026. 

& Dana Manual of Geology, pp. 554-555; 1895. 

See also report No. 64, U. S. Depart, of Agriculture. Division of soils, p. 54, gypsum formed from 
limestone in Texas. 

. Personally I am inclined to think that in most cases the genesis is inverse, the sulphuretted hydro- 
gen being the product of carbonated water, organic matter and gypsum. L. 


According to Lyell 1 , the thermal waters of Aix in Savoy in passing 
through the strata of Jurassic limestone turn them into gypsum, also 
the springs of Baden near Vienna deposit a fine powder composed of a 
mixture of gypsum, sulphur, and "muriate of lime. ,, In the Andes at the 
Puenta del Inca, a thermal spring contains a large proportion of gypsum 
and carbonate of lime. 

Mr. R. S. Sherwin* who has studied the gypsum deposits of Oklahoma 
regards the massive gypsum of this section as due to the alteration of 
limestone by the water of sulphur springs. 

Dawson*, following Lyell, explained the origin of the gypsum of Nova 
Scotia as follows: — First, there was an accumulation of numerous thin 
layers of limestone, either so rapidly or at so great a depth that organic 

Fig. 43. Limestone altered In part to gypsum, after Dana. 

remains were not included in any but tLe upper layers. Second, there 
was an introduction of sulphuric acid, in solution or in vapor, which was 
a product of volcanic action. Then for a long time the acid waters acted 
upon the calcareous material without any interruption from mechanical 
detritus. The limestone and calcareous matter are changed to the sul- 
phate, and gypsum of good quality accumulates in considerable thickness. 

§ 2. Hunt's Chemical Theory of Gypsum Formation. 

HuntV chemical theory of the formation of gypsuni is somewhat com- 
plex, but he believed it applied to a large part of the gypsum deposits of 
marine and fresh-water origin. In his own words the theory is as fol- 
lows : — 

"1. The action of solutions of bicarbonate of soda upon sea water 
separates, in the first place, the whole of the lime in the form of carbonate, 
anfi then gives rise to a solution of bicarbonate of magnesia, whi^h, by 
evaporation, deposits hydrous magnesiau carbonate. 

"2. The addition of solutions of bicarbonate of lime to sulphate of 
soda or sulphate of magnesia gives rise to bicarbonates of these bases, 
together with sulphate of lime, which later may be thrown down by 
alcohol. By the evaporation of a solution containing bicarbonate of 

> Lyell Principles of Geology, p. 216. 
a Transactions Kans. Acad. Science, Vol. XVIII. p. 85. 

("Origin of Gypsum at Plaister Cove, Nova Scotia," Quarterly Journal Geological Society, Vol. . 
V. p. 339, 1849. 
a Quarterly Jour. Geol. Soc. Vol. 16, p. 154, 1869. Chem. and Geol. Essays, pp. 80-92. 1878. 

184 GYPSUM. 

magnesia and sulphate of lime, either with or without sea salt, gypsum 
and hydrous carbonate of magnesia are successively deposited. 

"3. When the hydrous carbonate of magnesia is heated alone, under 
pressure, it is converted into magnesite; but if carbonate of lime be 
present, a double salt is formed, which is dolomite. 

"4. Solutions of bicarbonate of magnesia decompose chloride of cal- 
cium, and, when deprived of their excess of carbonic acid by evapora- 
tion, even solutions of gypsum, with separation of carbonate of lime. 

"5. Dolomites, magnesites, and magnesian marls have had their origin 
in sediments of magnesian carbonate formed by the evaporation of solu- 
tions of bicarbonate of magnesia. These solutions have been produced 
either by the action of bicarbonate of lime upon solutions of sulphate 
of magnesia, in which case gypsum is a subsidiary product, or by the 
decomposition of solutions of sulphate or chloride of magnesium by the 
waters of the rivers or springs containing bicarbonate of soda. The subse- 
quent action of heat upon such magnesian sediments, either alone or 
mingled with carbonate of lime, has changed them into magnesite or 

§ 3. Deposition of Gypsum Through Action of Pyrites Upon Carbon- 
ate of Lime. 

Pyrites or iron sulphide decomposing in clays may change the carbon- 
ate of lime into sulphate of lime, and so form gypsum, usually in small 
amounts and scattered through the clay. 

These crystals are found in the coal measure clays of Kansas (see Vol. 
V, Kans. Survey, p. 73) near the surface, and in size varying from micro- 
scopic crystals up to an inch in diameter. The neighboring shales are 
heavily charged with pyrite, which decomposes forming iron sulphate, 
which is carried in solution and acts on the limestone and shales. Gyp- 
sum produced in this way often forms very perfect crystals, but it is not 
of economic importance. 

§ 4. Gypsum Deposited in Rivers. 

Rivers may in some instances carry high percentage of sulphate of 
lime and so deposit gypsum at their mouths or in the basins into which 
they empty. Lyell in his Principles of Geology (p. 247) cites the river 
in Sicily known as La Fiume Salso, as an example of this method of 

§ 5. Secretion of Gypsum by Animals. 

In the cruise of the Challenger 1 , M. Buchanan found the Bathybius 
forming a sulphate of lime deposit. This unicellular animal belongs to 
the lowest group of animal life and forms slimy masses on the bottom of 
the sea. Many believe it is not an animal, but merely a deposition of lime 
salts in the water. 

J Lapparent Geologic p. 136. 


§ 6. Gypsum Formed from Anhydrite. 

Anhydrite (CaSO*) on taking up two molecules of water forms gyp- 
sum, and causes an increase in volume of 33#. According to Lapparent 
the force exerted by this change is four times as great as that of water 
freezing. This change on a small scale is found in many places, but in 
the Hartz mountains, according to Gary, the gypsum is formed from an- 
hydrite through the entrance of water. Near Ellrich the change has 
formed mounds of gypsum in concentric shells one and one-third meters 
(52 feet) high, often hollow in the interior. The force of the expansion 
has been sufficient to break crystals of quartz and dolomite in the layers 
above. 8 

§ ?• Gypsum Deposited from Sea Water. 

The most generally accepted theory of origin of large deposits of gyp- 
sum and salt has been that they are evaporated from salt water lakes 
or arms of bays and seas cut off from the main ocean. This theory has 
been given for the Iowa, New York, Virginia, and Kansas fields in the 
reports on salt and gypsum in those states. In the Kansas report, the 
writer endeavored to picture the history of the changes resulting in the 
evaporation of gypsum and salt laden water in a bay wiiose water re- 
treated to the southwest in Permian time. 

Examples of these changes can be found in the salt lakes and ocean 
gulfs and bordering seas at the present day. In southern Europe are 
excellent examples of the results of the evaporation of salt lakes, and in 
this country the best examples are seen in the Great Salt Lake and in the 
neighboring salt lakes of Utah and Nevada. Lake Bonneville in the 
(Quaternary period of geological time covered an area of 19.570 square 
miles with a depth of 1,050 feet, and its waters were fresh. Through 
evaporation, its level was lowered below the place of outlet at the north, 
and its waters in the course of time became more and more saline. This 
evaporation has continued until the present remnant, Salt Lake, has less 
than 2,400 square miles of area with an extreme depth of 50 feet, with 
its waters almost a concentrated brine with specific gravity of 1.1. The 
total amount of salts in this lake water is 15^, of which 11.8# is common 
salt (NaCl). 

The waters of the Dead Sea afford another example of concentrated 
brine due to evaporation. In this water there is 26# of salts, but differing 
in composition from the American lake. There is only 3.6$ of the com- 

» Possibly much of the Michigan gypsum has been anhydrite. The specific gTavity of gypsum beinc 
from 2.314 to 2.328 according to Dana and that of anhydrite from 2.800 to 2.985, the substance of gypsum 
in the shape of anhydrite and water (20.0& HoO plus 79.1% CaS0 4 ) would have a specific gravity of be- 

f 20.0 x 1 + 70.1 x 2.8000 to 2.085 ^ 
tween ± I = 2.401 to 2.660. 

I 100 

Therefore the substance of gypsum in the form of anhydrite and water is more condensed than in 
the shape of gypsum; therefore pressure would tend to aid its formation or change into the former 
shape. This may be the reason of the occurrence of anhydrite in the deep well samples, as well as 
its formation In boilers and similar places under pressure. L. 


186 GYPSUM. 

mon salt and 15# of the magnesium chloride as compared with 1.5# of 
this salt in the Great Salt Lake. The amount of gypsum in the waters 
of the two basins is nearly the same, 0.086#. The composition is given in 
the following table: — * 

Qreat Salt Lake. Dead Sea. 

Chloride of sodium 11.8628 3.6372 

Chloride of magnesium 1.4908 15.9774 

Chloride of calcium 4.7197 

Chloride of potassium 0.0862 0.8379 

Bromide of magnesium 05157 

Sulphate of calcium 0.0858 0.0889 

Sulphate of potassium 0.5363 

Sulphate of sodium 0.9321 

Water 85.0060 73.9232 

100.0000 100.0000 

Ocean water according to the analyses of the Challenger Reports con- 
tains 3.5# of mineral salts of which three-fourths is common salt, sodium 
chloride. The waters of the Atlantic show the following varieties and 
proportions of salts : — 

Per cent. 

Chloride of sodium (common salt) 77.758 

Chloride of magnesium 10.878 

Sulphate of magnesium 4.737 

Sulphate of lime (gypsum) 3.600 

Sulphate of potassium , 2.465 

Carbonate of lime '0.345 

Bromide of magnesium 0.217 


When such a body of water is cut off and evaporated, the gypsum is 
deposited after 37# of the water is removed, and common salt only after 
the removal of 93#. The normal order would be a deposit of gypsum and 
then a much heavier deposit of salt. But as 93# of the water must be 
evaporated before the salt would be thrown down, the evaporation might 
go far enough for the deposition of gypsum, but not far enough for the 
salt, or the salt might be deposited and subsequently removed by solution. 
The first condition apparently took place in the Kansas gypsum area, 
and both in Michigan. Gypsum deposits are more widespread in nature 
than salt, but they usually occur in thinner beds. 

In most areas the amount of gypsum found is far greater than the 
amount found in ocean water that would cover the area at reasonable 

» Geikie Text Book of Geology, p. 383; 1885. 


depths. The present condition in the Mediterranean sea seems to aid in 
the explanation of the formation of such deposits and has been cited for 
this purpose in the discussion of the Kansas 1 , Iowa 8 , and former accounts 
of the Michigan areas. 3 

§ 8. Mediterranean Sea. 

The most complete study of the composition and the currents of the 
Mediterranean sea have been made by Capt. Nares and Dr. Carpenter of 
H. M. S. Shearwater in 1871 . x They found the basin of this sea to be 

6,000 feet deep, separated from the ocean at the straits of Gibraltar by a 
ridge 1,200 feet high. The water of the Atlantic outside the ridge had a 
specific gravity of 1.026. In the western part of the sea the gravity is 
1.027, and at the eastern part of the sea it is 1.03. The proportion of salts 
in the ocean was 3.6#, and in the Mediterranean is 3.9#. Passing over the 
dividing ridge were two currents, one over the other. The upper was 
inflowing and the lower outflowing. The water of the basin is not con- 
centrated enough to deposit salt and gypsum, but it is gaining in quantity 
of salt held in solution. 

So it is thought that the water in the old seas or gulfs of Kansas and 
Iowa received additions of salt and gypsum by inflowing water and thus 
increased the thickness of the deposits. This theory is thought to ex- 
plain the great thickness of the salt deposits at Stassfurt (1,000 feet), and 
at Sperenberg (3,000 feet) in Germany, which could hardly have been de- 
posited except from a continuous supply of salt water. 

§ 9. The Michigan Carboniferous Salt Sea. 

The area of rocks in Michigan formed after the deposition of the Mar- 
shall and Kinderhook series is approximately circular in outline with a 
radius of 85 miles, giving an area of 22,686 square miles. As will be later 
shown, the sea covering this area in Osage time was 700 feet in depth, and 
assuming the average depth to be 326 feet, based on well records, there 
would have been about 1,280,000 billion gallons of water. 

The analyses of the Atlantic ocean water show 93.3 grains of gypsum 
to the gallon. If this Michigan sea had that proportion it would have 
yielded nearly nine billion tons of gypsum. 

The thickness of gypsum at Grand Rapids is 18 feet and at Alabaster 
is 20 feet. The approximate area at Grand Rapids is 24 square miles and 
at Alabaster, 10 square miles, and while the gypsum does not by any 
means keep this thickness given over these areas and is even absent in 
parts of the area, it has probably been removed by solution since its 
deposition. These conditions would give 1,237.764,000 tons of gypsum. 

University CJeol. Survey of Kan., Vol. V. p. 138. 

aiowaGeol. Survey. Vol. 12, p. 123. 

*Geol. Survey of Michigan. Vol. V, Part 2, p. 15. 

i Published In Proc. Roy. Soc. Vol. XX. p. 97. 414: 1873. cited in Enc. Brittanica, Vol. XV. p. 821. 

188 GYPSUM. 

If the assumption is made, that the gypsum covered all the area with 
a thickness of 20 feet 1 , then it would require 917 billion tons or 90 times 
the amount of water in this original sea, and one would need to look for 
the ridge or barrier over which the ocean waters flowed to supply the 
water for the gypsum, unless the same was supplied as in the Great Salt 
Lake by land drainage. 

§ 10. Caspian Sea. 

For a modern illustration of the conditions in this Michigan sea, the 
Caspian* sea might be cited. Into the northern part of this sea empty 
the Volga, Ural, and Terek, rivers bringing in a large quantity of the fresh 
water, so that the sea water is nearly pure, with a specific gravity of 
1.009. This small amount of salt, according to Von Baer, is partially due 
to the fresh water brought in and also to the number of shallow r lagoons 
surrounding the basin, each being a sort of natural salt pan. At Novo 
Petrovsk a former bay of the main sea is now divided into a number of 
basins showing all degrees of saline concentration. One of these has de- 
posited on its banks only a thin layer of salt, a second has the bottom 
covered with a thick crust of crystals, a third is a compact mass of salt, 
and a fourth has lost all the water and is a mass of salt covered with 
sand. On the other side of the sea in the peninsula of Apsheron are ten 
salt lakes from one of which 10,000 tons of salt are annually produced. 

The concentration is seen on the greatest scale in the Karaboghay 
(Black Gulf) of the Caspian, whose nearly circular shallow basin is about 
90 miles across, and almost entirely cut off by a long narrow spit of land 
communicating with it by a channel not over 150 yards broad and five 
feet deep. Through this passes a current with an average velocity of 
three miles an hour, accelerated by the western winds. 

This current is due to the indraught produced by excessive evaporation 
due to the heat and winds from the surface of the basin, which at the 
same time receives but little return from streams. The small depth of 
the bar prevents a counter current of highly saline water into the sea. 
The current carries into the Black Gulf, according to Von Baer, 350,000 
tons of salt daily. If the bar should be elevated and cut off the basin 
from the sea, the gulf would quickly diminish and become a salt marsh, 
later drying up and leaving a heavy salt deposit. North of this gulf 
over the Russian steppes are sands and marls intermingled with salt, 
representing former salt lakes now dried up. 

§ 11. The Michigan Caspian Sea. 

The Kinderhook sea of the American continent was an interior sea 

V'ith a bay extending north-east into Michigan. In this bay were 


(That a large part was covered is indicated by the occurrence of CaS0 4 also In the Alma. Midland 
Mt. Pleasant, and Bay City wells. 
* Von Baer, Bull. Acad. St. Petersbourg, 1865-6. quoted in Enc. Brittanica, VoL V, p. 176. 


laid down the Marshall sandstones. The close of the period was 
marked by an uplift in this area and a retreat of the sea southwest- 
ward, finally exposing a wide area of land in southern Michigan and 
northern Indiana. At Lafayette, Ind., the floor of this sea rose at least 
563 feet above sea level. 1 North of this land barrier was a large interior 
sea with a floor near Grand Rapids 375 feet above sea level, lower by 
nearly 200 feet than the ocean to the southwest, but surrounded by the 
Marshall series, at this time dry land 777 (Kalamazoo), 983 (Coldwater), 
to 1,000 feet (Hillsdale) above sea level on the south; 700 feet (Huron 
County) on the east; and 755 feet (Grayling) at the north; — a sea like 
the Caspian, with a depth at first of probably 700 feet or more, and an 
area of 22,686 square miles. 

In this sea were elevations and depressions, the ridge at Lansing 500 
feet above sea level, and a depression east of Saginaw r 380 feet below sea 
level separated by a ridge 187 feet above the sea floor. 

This sea probably had its tributary streams coming from the highland 
at the north and northeast flowing down across the recently emerged flats 
of the Waverly and Marshall land, bringing in a supply of sediment and 
doubtless salt and gypsum from the Salina beds at the north. 

The lake basins of Michigan and Huron were not in existence at this, 
time but belong to a much later chapter in the geological history of our 
continent. The irregular clay seams and the clay bedding planes in the 
gypsum represent an influx of sediment, wind blown material, or the 
result of tidal currents, or material brought in by streams. 

As the evaporation of these waters went on, the first deposit would be 
carbonate of lime thrown down when the specific gravity was raised to 
between 1.0506 and 1.1304. By further concentration, when the specific 
gravity was between 1.1304 and 1.22, gypsum would be deposited. At 
this time 37tf of the water must have been evaporated. If the sea was 
originally 700 feet in depth, it would now be 440 feet deep, still covering 
the Saginaw ridge but exposing the Lansing ridge. Thus would be formed 
smaller basins in which evaporation would go on rapidly. Further well 
records might give a clue to the other basins separated by ridges. The 
sea would gradually become like the modern Caspian with smaller basins 
around the main sea, in which all degrees of concentration would be 

In the deep basins near Saginaw, the dividing ridge would be exposed 
before the concentration produced the deposition of salt. In the evapora- 
ting basin the deposit of gypsum would occur especially around the 
borders of the basin, and by the influx at first of water across the Saginaw 
ridge the contracting basin of water was probably renewed, resulting in 
the 20 or 25 feet of gypsum in the area south. 

> The references are to present sea level. It is assumed that there has been no post carboniferous 



§ 1. Early Experiments. 

Ground uncalcined gypsum stone or land plaster, as a soil fertilizer, 
has at times been endowed, by writers on this subject, with the most 
wonderful and mysterious life-giving power. Other examples have been 
cited to show that it had no effect whatever, but such examples are 
rarely given in the earlier writings. From some of the accounts given it 
would seem as though land plaster used with certain crops would give a 
three years' yield in one. The good effects of land piaster have been 
assigned to its influence on the air, on water, and on the soil itself. 

Among the earliest accounts of gypsum as land plaster are those of 
Virgil who writes of the value of impure gypsum on cultivated fields, 
and the early farmers of Britain and of Lombardy had great faith in Its 

In this country, down to the year 1889 nearly two-thirds of the quarried 
gypsum was ground into land plaster. In the early 7CTs in Michigan, the 
mills could not supply the demand, though they were run night and 
day, and the material sold at a high price of $4.50 a ton. In 1890 the 
uses of gypsum in this country were reversed in ratio, and nearly twice 
as much rock was calcined as was used for fertilizer. By 1893 the pro- 
portion was three to one, and in 1898 the amount of gypsum calcined was 
six times that ground into land plaster. 

There were several causes for this change. One was the growing doubt 
with regard to the wonderful* properties of land plaster. Fields which 
had given greater yields by its application year after year, now failed to 
respond to the treatment. As it was sometimes expressed, the soil had 
grown tired of this form of food. Prof. F. S. Kedzie says that: — "Land 
plaster consists of elements which are rarely found deficient in soils. 1 
Hence it seems reasonable to suppose that the beneficial action of CaS0 4 
is certainly not direct but through secondary action. Its benefits are 
practically confined to the leguminous family, and the lessened use is due 
to a greater knowledge of what the crops remove from the soil, as well 
as to the discovery of phosphatic deposits and increased use of phosphatio 

1 CaO fs ul ways present, and SO-i verv eonimonlv in lower Michigan waters. See U. S. U. G. Water 
Supply, paper No. 31, ami annual report for 1902. ' 






On * 

V £ 

-< 3 

fa. * 

a & 


manures. Since the fertilizer law passed in 1885, the exact percentage 
of different constituent** in commonly used fertilizers is known. 

Then, also, commercial fertilizers composed of various ingredients be- 
came popular. Large companies were organized over the country, who by 
the use of large capital, careful preparation of materials aided often by 
judicious advertising were able to sell at a reasonable price patent phos- 
phate fertilizers embodying the good points of gypsum and giving other 
valuable qualities in addition. 

New uses for calcined plasters were devised especially in its use for 
hard wall plaster, Alabastine, Anti-Kalsoniine, etc., which enlarged the 
demand and opened a line of manufacture which proved more profitable 
than the grinding of the crude material. 

The opinions of agricultural chemists do not always agree and often 
opposite views are expressed in standard books of reference. The reports 
of agricultural societies down to about 1870 nearly always contained re- 
ports from farmers describing their experiments with gypsum on various 
crops. No agricultural treatise was complete without a discourse on this 
subject. At the present time it is rare to find gypsum discussed in such 
society meetings and modern books of agriculture devote but a paragraph 
to the subject of land plaster. The following is a list of references to the 
subject in the reports of the Michigan State Board of Agriculture : 

Gypsum Deposits in Michigan. 

Year. Page. 

1853 337 

1856 585 

1871 199 

1886 10U 

Plaster. Year. Page. 

a .i « i j S 1875 5»'l 

Action of, on land j j^q ^ 

a 3 *875 264 

Amount per acre to use -j j^ ^ 

Apple trees dusted with 1879 280 

Article on agricultural value of, by Dr. R. C. Kedzie. . . 1875 256 

Clover and 1877 149 

Compared with other fertilizers 1875 265 

Corn and 1878 162 

experiments 1877 78 

Curcullo, fought by 1888 224 

fl850 294 

I 1864 85 

Discussed i 1879 81, 91 

i 1883 100 

11886 74 

Drainage carrying out, of soils. 1875 262 

n ♦ # i S 1879 28Q 

Dust for Insects } jg^g 2 24 

Experiments with. 

("1865 236 

1866 56 

1877 78 

1878 215 

194 GYPSUM. 

Plaster. Year. Page. 

S1865 236 

1866 66 

{1875 264 

1886 72 

Liffht soils and 1864 19 

Lost by drainage 1875 262 

[ 1850 294 

| 1864 85 

Manurial value -1 1879 81, 91 

I 1883 100 

[1886 74 

Mixed with other things, effect of 1879 91 

Of Paris, manurial use of 1855 183 

Sowers 1878 373 

Used at Oravling 1888 209 

Wheat treated with 1875 265 


Ashes and salt, experiments with 1888 215 

Dust and carbolic acid for curculio 1888 224 

Used at Grayling 1888 209 


Effect on potatoes 1889 226 

rutabaga 1889 230 

Used on Grayling farm 1889 79 

The history of gypsum as a fertilizer 1 dates back a little over a hundred 
years. A century has seen its rise in the estimation of agriculturists and 
its decline. The land plaster industry started probably in Wurtemberg 
but was first brought to the attention of the world by the Economic 
Society of Berne, Switzerland. The first account that can be found of 
this use of gypsum is in the Mcmoires de la Society tfconomique de Berne 
in 1708. This society had submitted the following theme for public dis% 
cussion, "Description of the different kinds of earth and methods for 
mixing them to render the soil fertile." 

Among the papers submitted to the society was one by a clergyman, 
J. F. Mayer of Kupferzell in Wurtemberg, which was given first rank by 
the jury of the society of Berne. In the main paper there is no reference 
to gypsum, but in an appendix was a brief note on gypsum as a fertilizer, 
which according to Prof. Chuard brought about almost a revolution in 
agricultural methods of fertilizing soils. The society requested Mr. Mayer 
to give them further knowledge on this subject, which he did in the fol- 
lowing words: — 

(Translated from the French.) 

u It is only two years since one has entertained the thought that a stone 
of which little account was taken, was nevertheless well suited to attract 
to itself the oil and salt of the air, and consequently suitable to be placed 
on the meadows and to enrich them. When it is found crude, it is re- 

1 For the account of this earlv history, the writer is indebted to Prof. Chuard of Laussanne 
Switzerland, who has kindly placed at hand a number of his papers on this subject. 


duced to powder, and after it is crushed it is spread on the meadows or 
upon sterile soils of whatever nature they may be. Over one acre one 
scatters eight fri (a measure 13 inches in diameter and 8 inches high) 
and this fertilizer furnishes the best forage and the best clover one can 
imagine. It has greater effect if calcined, but the best effect is obtained 
by adding to it two fri of wood ashes and eight handsful of salt, and the 
whole soaked in a half pail of manure water. Let these materials be 
well mixed, then let them lie eight days, after which having stirred them, 
one may spread them on the soils to be fertilized. Our people profit by 
it continually and the experience for two years has justified the first 
trials. As soon as one is quite convinced, and one cannot conceive it 
otherwise, that all plants are composed of salt. oil. and earth, one will 
be as easily persuaded that gypsum flour scattered over wheat, oats, 
barley, and vegetables, ought to produce the same effect. The experiment 
has already been tried." 

The society of Berne realizing the importance of this communication, 
decided to have the experiments at Kupferzell repeated at a number of 
places, and these results were published in the Memoir for 1771, espe- 
cially in two communications, one by N. IT. Kirchbergner, and the other 
by M. Tschiffeli. 

The paper by Kirchbergner is an account of a series of experiments on 
clover, lucerne, and radishes, and the author expresses his admiration 
over the marvelous results obtained from the use of this gypsum fertil- 
izer. On an acre (arpent) twelve measures of gypsum, costing three 
francs and twelve i>ence produced more forage than 12 cars of manure 
costing not less than 72 francs. He preferred calcined gypsum to raw, 
not for the effect but because it was more readily pulverized. The gyp- 
sum produced a greater effect the first year but also gave an increase in 
crops the second year. It had more effect on dry earth than on wet, was 
better on heavy soil than light. Sowed in the spring on natural forage it 
produced its best effects on the second cutting. 

The memoir of Tschiffeli proved at the start that gypsum was excellent 
material for the soil and not injurious. The conclusions of the experi- 
ments were the same as in the first memoir. On wheat becoming weak 
in its growth at the first of June, gypsum applied in double portion at a 
dry time, brought about at the first rain an almost miraculous growth 
and made a good harvest. Both of these men observed that no culture 
profited with gypsum like trefle, luzerne and the plants of this same 

These experiments were repeated by others and the use of gypsum 
fertilizer spread over France, then over Germany and England, and be- 
came especially prominent in the United States where the gypsum was 
imported from the Monte Martre quarries near Paris. 

196 GYPSUM, 

§ 2. Early Use in America. 

The early farmers in Maryland, according to Rees, used gypsum fertil- 
izer with great success, and this writer states that : 

"It was most beneficial on high and sandy soils and had good effect 
on wheat, rye, barley, peas, potatoes, cabbage, clover and all natural 
grass crops. The invariable result of the several experiments incon- 
testibly proves that there is a most powerful and subtle principle in this 
tasteless stone, but by what peculiar agency or combination it is capable 
of forcing vegetation in such an instantaneous and astounding manner 
is a mystery which time reserves for others to unfold." 

Benjamin Franklin called attention to the value of gypsum as a fertil- 
izer for grass, by sowing the land plaster in a clover field near one of the 
main roads in Pennsylvania so as to form the sentence, "This has been 
plastered with gypsum," and the letters it is said could be detected readily 
by the height and color of the clover where the gypsum had been sown. 

Ghrece'a American Observations. 

Mr. Chas. F. Grece 1 writing of his observations in the United States 
and Canada in 1819 in the Quarterly Review, says: 

"This valuable manure, almost unknown though very easy to obtain, 
merits the attention of every farmer. There is scarcely a farm in the 
provinces but it might be applied to with advantage. The practice of 
nine years on the following soils and crops may suffice to prove its 
quality. On a piece of poor yellow loam I tried three grain crops with- 
out success, with the last which followed a hoe crop I laid it down with 
barley and the return was little more than the seed. The grass seed took 
very well. In the month of May of the following year I strewed powder 
of plaster at the rate of one minot and one peck to the arpent (acre) . 
In July the piece of land being mowed the quantity of the grass was so 
great that it was not possible to find room to dry it on the land where 
it grew. The product was five large loads of hay to the arpent. It 
continued good for five years. ... I tried plaster on cabbages and 
turnips, but did not perceive any good effects. From the frequent trials 
of this manure on various soils it is evident that it is applicable to both 
light and strong soils for top dressing of succulent plants." 

Ruffin's Experiments. 

Ruffin, in his book on Calcareous Manures, 2 written in 1832, states 

"There is no operation of nature heretofore less understood or of which 
the cause or agent seems to be so totally disproportionate to the effect 
as the enormous increase of vegetable growth from a very small quantity 

I VoL XXIII, pp. 147-150; 1820. 
a Page 151. 


of gypsum in circumstances favorable to its action. All other manures, 
whatever may be the nature of their action, require to be applied in 
quantities very far exceeding any bulk of crop expected from their use. 
But one bushel of gypsum spread over an acre of land fit for its action 
may add more than 20 times its own weight to a single crop of clover 

Mr. Harbe 1 in the German Land-Owners meeting in 1841. stated that he 
had found gypsum of most value on clover and peas. If applied to peas, 
and oats were planted the next year, there was a greater yield, but the 
plaster applied directly to an oat field produced no effect. The discussion 
at this meeting brought forth contradictory remarks with regard to the 
use of gypsum on meadows. In the Gardener's Chronicle for 1841 (p. 
785), gypsum was stated to be of little use on corn, but useful for clover, 
grass, potatoes, and turnips, and was especially good on light or chalky 
land and should be sown broadcast in proportion of about five bushels to 
the acre. 

Harris' Experiments. 

Mr. Harris, 2 in 1878, gave an account of his experiment on oats at the 
Moreton farm near Rochester, N. Y., in the following table: — 

Bushels to Weight per Pounds of 
acre. bushel. straw. 

On field No. 1, without manure 36 22 1068 

On field No. 2, with 600 lbs. of gypsum 47 26 2475 

There was an increase of 11 bushels to the acre, and nearly one-half 
ton more straw. 

Bushels to 
the acre. 

On potatoes with no manure 1)5 

" " " 100 pounds of plaster to the acre 101 

" '* " 150 pounds of ammonia sulphate 140 

He did not find gypsum valuable as a direct fertilizer for wheat, but 
quotes an old adage that, "clover is good for wheat, plaster is good for 

§ 3. Theory of De Candolle and Chaptal. 

The early theory to explain the action of gypsum on soils, very at- 
tractive and popular in its day, was that of De Candolle/ who looked 
upon gypsum as a stimulant to the leaves of plants. This theory, which 
became prevalent, stated that "sulphate of lime acts as an irritant in 
favoring respiration and exhalation of plants." 

Chaptal modified this theory somewhat, and regarded the stimulation 

i Agricultural Society of England. VoL 883. p. 224; 1812 
tTalks on Manures, pp. 126, SM: 1878. 
* Add ale* de Cnimle, M, p. SIS. 



as due to the saline character given to the sap by the presence of gypsum, 
and as this mineral dissolved very slowly, it would gently stimulate and 
not irritate. 

§ 4. Gypsum as Direct Plant Food. 

The examination of the ash of plants was made long ago, and formed 
the basis for a number of theories concerning the action of plaster on 
plants, especially for those theories which regarded gypsum as a direct 
element of plant food. 

Analyses of Plants. 

Pasture g rass 

Red clover, young 

" •* in hud 

•• " In flower. . 
Alfalfa, (early flower). 
White clover, In flower 

Potato plant 

Oats (grain) 

Maize (grain) 

Spring wheat (grain) . . 
Winter wheat (grain). . 
Garden beans (seed) . . . 









17 6 








2* 7 


16. B 



4 5 



4 H 














I 2 





























4 3 




































The translation of the German work by Prof. Sprengel, published in 
the Agricultural Gazette in 1844 (p. 858), states that gypsum suffers no 
decomposition in the soil but passes in its entire state into the substance 
of the plant. 

According to Johnston, 1 in 1849, the benefit of gypsum to clover is due 
to its decomposition in the soil, thereby furnishing lime and sulphur to 
the plants. This author believed the gypsum did not fix ammonia, and 
further absorbed very little moisture from the air. According to his ex- 

1000 parts of Boot gained from moist air 36 parts by weight. 
" u " coal ashes gained 14 parts by weight. 
44 " " burnt clay " 29 " 4 - 

44 44 chalk kt 4 44 4 ' 44 

" 4i gypsum *• <J k - 4 ' 44 

§ 5. ltetention of Ammonia by Gypsum. 

Moist gypsum in contact with ammonium carbonate has been supposed 
to form ammonium sulphate according to the formula, 8 
(NHJ 2 C0 8 +CaS0 4 =(NHJ 2 S0 4 +CaC0 3 
If used in stables and other places it serves to retain to some extent the 

1 Manures, pp. 454-481; 1844. 

Use of Jime In Agriculture, p. 304; 1840. 

?U. S Dept. of Agric. No. 64. Division of Soils. 1800, Cameron, p. 155- 


ammonia which otherwise might escape into the air. This use of land 
plaster is recommended by Snyder 1 and also by Wiley. 2 

It was early discovered that the atmosphere contained carbonate of 
ammonia which was carried down to the earth in rain water, and there 
it was thought to be held or fixed by gypsum. A good statement of this 
theory is given in Browne's American Muck Hook. 3 written in 1S51. The 
carbonate of ammonia acted on the sulphate of lime so as to form sulphate 
of ammonia and carbonate of lime. This prevented the escape of the 
volatile carbonate of ammonia back into the air. A computation was 
made which showed that 100 pounds of common unburned gypsum would 
fix 20 pounds of ammonia containing 16^> pounds of nitrogen. This 
would furnish a very large amount of valuable food to plants for their 
use; but now it is known that the amount of ammonia in the air is so 
small that it is very doubtful whether the amount so fixed by gypsum is 
even appreciable to the plants. 

This theory was held and much elaborated by the chemist Liebig, who 
calculated that if 40 pounds of gypsum were placed on a field, and only 
one-tenth of it entered plants as ammonia sulphate, theoretically there 
would be nitrogen enough for 100 pounds of hay, 50 pounds of wheat, or 
60 pounds of clover. 

Stockhardt'8 Theory. 

Some have held that the gypsum fixed the ammonia formed within the 
soil by decaying vegetable matter; and further, that the gypsum hastened 
this decay. Davy tried a number of experiments to disprove this latter 
statement and he found that meat mixed with gypsum and allowed to 
stand a considerable period of time showed not the slightest difference 
in time of putrefaction, from meat not so treated. The former part of the 
theory is jriven in a brief summary by K. Stockhardt : 4 

"Gypsum acts chiefly through its sulphuric acid, which on the one side 
procures soluble ammonia from the humous constituent of the soil and 
furnishes ttiis to the plant at the period when it is especially inclined 
to the production of leaves and stems; and on the other side, strengthens 
and increases the power of plants to absorb ammonia from the atmos- 
phere, and this in greater proportion as they are more abundantly en- 
dowed with delicate and juicy leaves and are thus already fitted by nature 
to make a more abundant use of the atmosphere." 

S G. Van Wormer's Experiments. 

Experiments by Lewis 11. Van Wormer on the fixation of ammonia by 
land plaster conducted under the direction of F. S. Kedzie for a senior 
agricultural thesis in the Michigan Agricultural College in 1895, seem 
however, to show that dry plaster has but little power to absorb and 

• The Chemistry of Soils and Fertilizers, p. 161. 1800. 

'Principles and Practice of Agricultural Analysis, VoLS, pp. 307-308: 1895 
"Pages 68 to 75. 

* A Familiar Exposition of the Chemistry of Agriculture, p. 396: 1885. 

200 GYPSUM. 

affix ammonia. Dampened plaster absorbed ammonia but lost most of 
it on drying out. This led Mr. Van Wormer to conclude that the power 
of absorption depended more upon the water than upon the plaster. It 
seems, however, to be possible that the water acted as a necessary medium 
for reaction and that then the reaction above stated may have gone on. 
Mr. Van Wormer experimented under conditions both abnormal and 
normal. In one set of experiments he placed under bell jars a watch glass 
of ammonia and a watch glass of plaster or some other substance under 
each. Five grams of dry plaster under the jars with live c.c. of ammonia 
left for more than ten days contained only from 0.1 to 0.2 c.c. of ammonia 
less than would be absorbed by 3. c.c. of water. In only 48 hours it con- 
tained 2.5 respectively 3.3 of ammonia. 

Another line of experiments was to place water, plaster and sulphuric 
acid in crystallizing dishes under the floor of a stable reeking with am- 
monia. After four days 15 grams of plaster moistened with 15 c.c. of 
water, 15 c.c. of water straight and 15 c.c. of sulphuric acid had absorbed 
relatively 25.8, 10.8, and 199.4 c.c. of standard decinormal solution of 
ammonia containing 1-7 grams of ammonia per liter of water. 

A similar experiment with 5 grams of plaster and 5 grams of sand 
each added to 5 c.c. of water, gave for the plaster 7.4 and 4.3 c.c. of the 
ammonia solution in four days, and in another case 3.5 to 1.3 c.c. 

In testing plaster in comparison with muck (peat) in a similar way 
5 grams of each with excess of water absorbed in three days 10.2 c.c, and 
32.1 c.c. respectively and in 24 hours 7.5 and 34.3 c.c, and in three days 
under the stable floor 6.6 to 31.5 c.c. In an experiment under bell jars 
with barely enough water to wet the two that ratio was 1.7 c.c. to 37 cc, 
again in favor of the muck. Further experiments show that muck or peat 
was a much more effective fixing agent than plaster. 

§ 7. Houssingault/s Experiments. 

Boussingault. 1 in 1841 spread gypsum over a clover field, and then 
analyzed the clover from the land where gypsum was spread and where 
it had not been spread. He found a great increase in amount of ash, which 
represented an increase in all the mineral constituents, but especially in 
lime, magnesia, and potash. These experiments, carried on for two years 
on the same land, are given in the following table: — 

Land with No Land with No 
gypsum. gypsum, gypsum, gypsum- 
Ashes free from CO a 270.0 113.0 280.0 97.0 

Silica 28.1 22.7 10.4 12.7 

Oxides (iron, manganese, alumina) 2.7 1.4 V 0.6 

Lime 79.4 32.2 102.8 32.2 

Magnesia 18.1 8.0 28.5 7.1 

Potash 95.6 26.7 97.2 28.6 

Soda 2.4 1.4 0.8 2.8 

Sulphuric acid 9.2 4.4 9.0 3.0 

Phosphoric acid 24.2 11.0 22.9 7.0 

Chlorine 10.3 4.6 8.4 3.0 

I Rural Economy. 1887. 


\'»l IX l**irt II I'iuir XXIV 


round plan, 
round plan. 
iikI plan. 


This table gives the number of kilograms of the elements in clover from 
a hectare of ground, and it certainly shows that gypsum has had con- 
siderable effect on the clover. The great increase of potash shown by 
these analyses was explained as due to the direct action of the gypsum on 
the soil or was left out of account altogether. It is explained in another 
way by more modern theories as will be descril>ed in another section. 

§ S. Davy's Theory. 

Sir Humphrey, and others before and after his time, have regarded 
gypsuni as a direct source of plant food. Davy found that clover con- 
tained about two hundred weight per acre of sulphate of lime, and that 
this was the amount of gypsum which produced the greatest benefit on 
the soil, so he argued the gypsum entered the plant as sulphate of lime. 

An examination of the table of plant composition given above shows 
that lime and sulphuric acid are present in the plants benefited by the 
gypsum. Other tables give sulphur as an element in plant ash rather 
than sulphuric acid. So sulphur was supposed to come from the gypsum 
which did hot enter directly as plant food, but was first broken up into 
its parts. This action was supposed to depend on the presence of humous 
acids, whereby the gypsum was broken up into humate of lime and 
sulphuric acid. If too little humus was present this action would not 
take place, and on such soils gypsum would be of no value; if too much 
humus, the action would be rapid, setting free so much sulphuric acid 
that it would corrode the roots of the plants and so prove injurious. 
The lime shown in the table of plant analyses was supposed by many to 
result from the decomposition of the gypsum. 

The sulphur of plants probably comes from other sulphates more easily 
decomposed than gypsum, though a small portion may result from this 
mineral. Most of the lime is certainly derived from other compounds, 
especially the carbonate of lime, which is readily soluble. 

§ 9. Recent Theory of Storer. 

Gypsum is now 1 thought to act as a fertilizer of soils in three ways, 
one mechanical and two chemical. 

First, lime is known to flocculate loose soils; that is, collects together 
the loose particles and so makes the soil more granular. This may be 
illustrated by placing lime in a muddy liquid, and the mud Will flocculate 
and settle to the bottom. Lime has also an opposite effect on tough clay 
soils, where it granulates them, breaking the soil up into finer particles. 
Gypsum as a lime salt, appears to act to a small extent in these ways and 

• Chemistry of Agriculture. VoL 1, pp. 806-216; 1887. 

202 GYPSUM. 

80 improve the mechanical condition of the soils; but in this respect other 
lime compounds act more powerfully and more rapidly, and so would l>e 

Second. Storer has pointed out that gypsum has nearly one-half its 
weight in oxygen and gives this up to many substances, and so may act 
upon nitrogenous and carbonaceous substances in the soil. 

Third, and most important, it has been shown that gypsum decom- 
poses the double silicates in the earth, setting free ixttash as a double 
sulphate. According to Storer the action is as follows : 

A1A, | ( A1 2 0, 1 

&5? x SiO. + CaOSQ, = 1 2*2 I x SiO a + K» OSO . 

H 2 G 

J CaO | 
1 CaO r 
l H 2 J 

By this means the potash in solution reaches the roots of the plants. 
This method of supply is of special advantage to the deep rooted plants, 
as in the order Leguminosae — the clovers, beans, etc., which contain a 
considerable percentage of potash in their tissues. 

Soils with abundant potash would not need gypsum, and soils with no 
potash compounds would not be benefited in this respect by gypsum. 

The gypsum is then to be looked upon as an excitant rather than as a 
form of plant food. Land plaster according to this theory uses the 
potash of the soils more readily than it is used naturally and so after a 
few years the soil fails to respond to the gypsum dressing, and the soil 
is said to have grown tired of this treatment. The experience of many 
farmers is that gypsum is very beneficial for a few years and after that it 
fails to produce any effect. This is expressed in the old English adage, 
"Lime enriches the father, but impoverishes the son." 

§ 10. Experiments in Kansas. 

Recent experiments made in Kansas 1 on prairie and tame grasses ap- 
pear to show that on the soils in the Manhattan region, plaster has but 
little effect. 

On prairie grass the average yield on non-plastered plats was 1.248 
tons to the acre. On plastered plats the yield was 1.250 tons. 

The experiments on tame grass are shown in the table : 

Total yield 
1st cutting. 3d cutting- per acre. 
Pounds. Pounds. Tons. 

Plaster, 800 pounds per acre i,076| 0761 3.506 

Plaster, 400 pounds to the acre 1.012* 690 3.404 

Nothing 1 .008 690 3.396 

'BulL 32 Kansas State Agricultural College Experiment Station, pp. 239, 240: 1891. 
Bull. 30. p. 201.202: 1891. 


The experiment gave an increase on the plastered land of 1G5 pound* of 
hay on one and one-fourth acres, and the fertilizer cost of this land was 

On corn the yield on non-plastered acre plats was 71.3 bushels to the 
acre; on plastered plats the yield was 70.0 bushels, and in another ex- 
I»eriment the increase through the use of plaster was on<»-1enth of a 


§ 1. Uncalciued Gypsum. 

Gypsum in its grouud uncalcined state is used as land plaster for 
fertilizer on various soils. Its value in this connection is much disputed 
and doubted, and the subject is discussed in the previous chapter. Com- 
mercial patent fertilizers have displaced this form to a very considerable 
extent. Many of these, however, have a base of gypsum to which are 
added the various other ingredients. 

Terra Alba. 

The white, finely ground, crude gypsum is sometimes sold under the 
name of terra alba for adulteration purposes. This substance is some- 
times mixed with white lead paints, making a cheap substitute for the 
lead. It has been detected in flour, sugar, candy, baking powders, and 
other compounds. The pure food laws in a number of states have been 
instrumental in detecting a wide range of such illegitimate uses. 

In India, powdered gypsum is kept iu the bazaars as a drug. It is 
supposed to have cooling properties, and a gruel made from it is given 
in fevers. It is also used by the Chinese in a similar way. In India it is 
also calcined and used for chewing with betel, though sometimes carbon- 
ate of lime is used instead. 

Gypsum is sometimes added to the water used in brewing. Soft water, 1 
free from saline matter is not good for brewing purposes, so sodium 
i-hloride and gypsum are added. The English laws allow this to be 
added .up to 50 grains per imperial gallon. Soft water gives higher ex- 
tracts as it dissolves the albuminous matter in the malt more effectually 
than in hard water, but the impurities are powerful agents of change. 
Lower Michigan waters will rarely need gypsum added to them. 1 

The famous Burton ales in England are made with water from wells 
which pass through the gypseous deposits in the Keuper marls of the 
district. This water is considered especially desirable for brewing. Its 
composition is as follows, in an imperial gallon of 10 lbs.=70,000 grains : 

•Encyclopedia Brittanica, Vol. IV, p. 275. 
*See U. S. G. S. Water Supply, Paper No. 81. 



Chloride of sodium 10.12 

Sulphate of potassium 7.G5 

Sulphate of lime 18.90 

Sulphate of magnesia 9.95 

Carbonate of lime 15.51 

Carbonate of magnesia 1.70 

Carbonate of iron 0.00 

Silicic acid .". 0.79 


In another large brewery at Burton, analysis shows the water to con- 
tain 54.5 grains of sulphates and 9.93 of carbonate of lime. 

Gypsum flour or terra alba is mixed with poorer grades of wheat flour 
and used for dusting the moulds in metal casting. The mixture is sold 
under the name of Corine flour. 

The crude gypsum is used in the preparation of some pharmaceutical 
preparations. It is also used in some methods of decomposing ammonia 
in the manufacture of sal-ammoniac. 

Thin plates of selenite are sometimes used in optical work to determine 
the positive and negative character of minerals, and as it does not trans- 
mit heat well it is used to protect the lenses of optical lanterns. 

Garnierite or the hydrous silicate of nickel, is mined in New Caledonia, 
and it is one of the important sources of nickel. The ore is smelted in a 
low blast furnace with coke and gypsum. 

In Michigan, a special branch of manufacture is that of bug plaster, 
which is a land plaster mixed with Paris-green or other poison and used 
on potatoes and vines to destroy the insects. As a base of insecticides 
it is widely used. 

Manufacture of Crayons. 

Chalk crayons for blackboard and carpenter's use, are now commonly 
made from gypsum. The ground uncalcined gypsum is mixed with other 
ingredients according to a secret formula, pressed and dried and packed 
in boxes. One of the largest companies engaged in this work is the 
American Crayon Co., of Sandusky, Ohio, established in 1835. Their new 
works, completed in the fall of 1902, is the largest factory of this kind 
in the United States. They manufacture a variety of products besides 
crayons. The company sells annually about 18,000 cases of crayons, re- 
quiring 80 pounds of gypsum to the caw\ or 720 tons a year. The gypsum 
is obtained from the Marsh quarry at Port Clinton. 

206 GYPSUM. 

Hardening of Gypsum Blocks. 

Various methods have been devised to harden blocks of gypsum to 
imitate marble. A Canadian company a few years ago quarried large 
blocks out of the Alabaster quarry with a channeling machine. These 
blocks were shipped to near Toronto and hardened, but for some reason 
the work was abandoned. Some of the Michigan gypsum has been hard- 
ened at Chicago, but the work has been on a small scale. A Chicago 
company a few years ago established a factory for making this artificial 
marble at Canyon City, Colorado. 

A number of patents have been issued for this work. Patent number 
549,151 (1894) by Mr. Geo. W. Parker, formerly of San Francisco, is en- 
titled "Process of Treating Gypsum Rock to Imitate Chalcedony." The 
claim is as follows: 

"The process of treating gypsum rock to represent chalcedony coA- 
sits in first completely dehydrating the rock by the action of hot air, 
next allowing the now porous rock to absorb a solution of sulphate 
of iron, nitric acid, and potassium sulpho-cyanide, after which immersing 
in a solution of aluminum sulphate [Al 2 (SOJJ for fifteen hours, next 
expose to air and then polish as set forth." 

Patent number 588,287 (1897) by Geo. W. Parker of Grand Rapids, 
(filed October, 1895; renewed, July, 1897), is entitled "Gypsum Rock to 
Imitate Marble.'' The claim is: 

"The process of treating gypsum rock which consists of eliminating 
the moisture from the rock by the action of hot air, then removing the 
then hot calcium sulphate into a closed compartment charged with the 
fumes of ammonia and then immediately immersing the cool rock in a 
warm solution of aluminum sulphate until the pores are filled, as set 

Hardened gypsum treated with stearic acid or with paraffine and pol- 
ished, resembles meerschaum, and it is used for cheap pipes. Sometimes 
coloring solutions of gamboge are added to complete the resemblance. 1 

Use of Uncalcined Gypsum in Portland Cement. 

A small amount of gypsum added to Portland cement, retards its set 
and apparently does not injure its tensile strength. Large amounts will 
retard the set of the cement and also give it a greater tensile strength, 
but after a time the set cement will begin to check. 

In one briquette tested which had been mixed with a high percentage 
of gypsum, the tensile strength in 24 days was 1,100 pounds, with no 
trace of cracks or checks. This broken briquette is now over a year old, 

i Wagner, Chemical Technology, p. 833. 1889. 


and it is badly checked and cracks extend nearly half way through the 

According to Michaelis, 1 gypsum may be added to cement in amount 
up to four per cent by weight to increase the hardness, though the Ger- 
man regulations and those of the London Chamber of Commerce permit 
but one-half of this amount. 

This writer states that the gypsum in the cement takes the form of 
calcic aluminate, Ca,Al 2 O fl +3 CaS0 4 +n H 2 0, the n probably equalling 
30. This substance crystalizes in needle shaped rods of one-half milli- 
meter in length. Most Portland cements have seven to nine per cent of 
alumina and can take up 28 to 30 per cent of calcic sulphate and water. 
If in larger quantities these crystals forming and expanding will break 
the cement. 

The experiments of Oandlot' nhow the following influence of gypsum 
on the cement. 100 grams of cement are used and the amounts of gypsum 
added as shown in the first column. 

Grams of Initial set. Final set. 

gypsum. Hours. Minutes. Hours. Minutes. 

0.0 7 22 

0.5 50 2 40 

1.0 2 40 4 50 

1.5 2 57 5 17 

2.0 3 00 5 20 

3.0 3 00 K 40 

4.0 ., 3 30 7 00 

According to Candlot, the time after the mixture is made has its effect 
on the setting of the cement. A mixture of cement with three ]>er cent 
of gypsum showed the following variation with time: 

Initial set. Final set 

Hours. Minutes. Hours. Minutes. 

On day of mixture 1 00 7 00 

4 days after mixture 5 2 15 

7 " «■ 4 * 5 .20 

11 " il «• 8 30 

15 5 30 

32 •' * 4 lk 10 30 

41 45 5 30 

llift explanation of the influence of the gypsum on the cement is that 
the gypsum combines with the aluminate of lime and loses all its water 
at 300° and forms a sulpho-aluminate of lime with the formula (A1 2 3 
3CaO) 2y» SO a CaO). He states that in Portland cement there is always 
some free lime and very little alumina. As this free lime dissolves 
rapidly, it hinders the hydration of the alumina. The sulphate of lime 
added to the cement is not able to combine with the alumina and adds its 
action to that of the lime to hinder the hydration of the aluminate. The 
set is ascribed to the aluminate, and the gypsum hinders its hydration. 

•The Cement Bacillus by Dr. Wllhelm Mi haelis. The Eng. Record, Volume », p. 110. 1001. 
tCandlot, Ciments et Chaux Hydrauhques (Paris), p 836; IttfB. 

208 UYl'SUM. 

According to Dibdin 1 the gypsum is first dissolved and then precipitated 
in very tine particles* on the grains of cement, so the chemical incorpora- 
tion of the water in the cement is delayed. By some simultaneous oc- 
currence of some chemical action the cement has greater strength. 

The inlluence of gypsum on the strength of the cement is shown in the 
following table from Dibdin: 

Breaking weight in pounds of briquettes of one square inch section 
after 2S days. 

No. 1. No. 2. 

With no gypsum 018 800 

0.1 per cent gypsum 587 693 

0.3 " " - 030 750 

0.5 (523 777 

0.7 " " " 590 813 

1.0 090 823 

1.5 •• " •• 057 890 

2.0 013 8G0 

§ 2. Calcined (Jypsuin. 

When gypsum is calcined it is known as plaster of Paris. The finer 
grades are sold as dental plaster and as plaster of Paris for the manu- 
facture of casts and moulds. It is also used for white finish on the walls 
of buildings. Dental plaster is usually reground and carefully sifted so 
as to give a superfine plaster free from grit. Our museums of art show 
the large use of plaster for moulds and casts of ancient works of art and 

Plaster was prepared at the old Phoenix Plaster Mill of New York 
city for glazing porcelain, a use which has apparently disappeared with 
lime, other forms of glaze being regarded as better adapted to this w r ork. 

It lias also been recommended by Prof. Moses of Columbia University, 
for use in place of charcoal in blow pipe tests. 

S 3. Wall Plaster. 

In this country, gypsum wall plasters known under the names of rock 
wall plaster, hard plaster, cement plaster, adamant, etc., are either mix- 
tures of plaster of Paris and retarder, or of plaster of Paris, retarder 
and sand. Such plasters set slowly and are applied to the walls in the 
same way as lime plasters. 

Strength of Wall Plasters. 

In determining the hardness and strength of wall plaster the French 

workmen are accustomed to ascribe the strength of the plaster to the 

hardness of the original gypsum rock. So that other conditions being 

equal, according to the French rule, the harder the gypsum rock, the 

. stronger the plaster made from it. 

•Lime. Mortar and Cement, by Dibdin (London), p. 188: 1868. 

Geological Survey of Michigan. Vol. IX, Part II, Plate XXV. 



In Plain and Relief Work, 


















B J 









83 | 






208 GYPSUM. 

According to Dibdin 1 the gypsum is first dissolved and then precipitated 
in very fine particles on the grains of cement, so the chemical incorpora- 
tion of the water in the cement is delayed. By some simultaneous oc- 
currence of some chemical action the cement has greater strength. 

The influence of gypsum on the strength of the cement is shown in the 
following table from Dibdin : 

Breaking weight in pounds of briquettes of one square inch section 
after 28 days. 

No. 1. No. 2. 

With no gypsum 618 800 

0.1 per cent gypsum 587 693 

,0.3 " " " 630 750 

0.5 " •* " 623 777 

0.7 " " " 590 813 

1.0 " " " 690 823 

1.5 " " '• 657 890 

2.0 •• " " 013 860 

§ 2. Calcined Gypsum. 

When gypsum is calcined it is known as plaster of Paris. The finer 
grades are sold as dental plaster and as plaster of Paris for the manu- 
facture of casts and moulds. It is also used for white finish on the walls 
of buildings. Dental plaster is usually reground and carefully sifted so 
as to give a superfine plaster free from grit. Our museums of art show 
the large use of plaster for moulds and casts of ancient works of art and 

Plaster was prepared at the old Phoenix Plaster Mill of New York 
city for glazing porcelain, a use which has apparently disappeared with 
time, other forms of glaze being regarded as better adapted to this work. 

It has also been recommended by Prof. Moses of Columbia University, 
for use in place of charcoal in blow pipe tests. 

§ 3. • Wall Plaster. 

In this country, gypsum wall plasters known under the names of rock 
wall plaster, hard plaster, cement plaster, adamant, etc., are either mix- 
tures of plaster of Paris and retarder, or of plaster of Paris, retarder 
and sand. Such plasters set slowly and are applied to the walls in the 
same way as lime plasters. 

Strength of Wall Plasters. 

In determining the hardness and strength of wall plaster the French 

workmen are accustomed to ascribe the strength of the plaster to the 

hardness of the original gypsum rock. So that other conditions being 

equal, according to the French rule, the harder the gypsum rock, the 

. stronger the plaster made from it. 

'Lime, Mortar and Cement, by Dibdin (London), p. 188; 1868. 


The Paris gypsum contains a high percentage of lime carbonate (12#), 
and it makes a plaster of high strength, but Gay Lussac pointed out that 
this was not due to the lime carbonate directly, as the lime carbonate 
was not altered at the temperature used in burning gypsum, but the lime 
still might add to the more equal distribution of the heat and help to 
avoid the danger of overburning. 

The amount of water used in guaging the plaster is also important in 
determining the strength of the resulting product. To obtain all the 
strength of the plaster it is stiff gauged (gache serre) by adding very 
little water. In making the finish plaster more water is added than be- 
fore the plaster is guaged thin (gache clair). 

In the use of ordinary lime plaster three coats are usually applied to 
the wall. The first rough or scratch coat, composed of lime and sand, is 
applied to the wall or lath and dried in ten days to two weeks. It is 
common to scratch or furrow this coat with a trowel so that the second 
coat will adhere more firmly. The rough coat must be thoroughly dry 
l>efore the second or brown coat is applied. In composition the second 
coat is practically the same as the first and dried in about the same time 
or a little longer. 

The last or finish coat is applied after the second is thoroughly dry. 
It is made from slaked lime putty made two or three weeks before it is 
used, mixed with plaster of Paris, and pure white, fine sand, or from a 
mixture of plaster of Paris and lime putty. The workmen must then 
wait until the wall is thoroughly dry before the wood work can be nailed 
on the walls. 

In working with gypsum plasters, the first or rough coat is applied 
and before it is set the second or brown coat is applied and thoroughly 
pressed into place with the first one. This makes practically one coat of 
plaster, three-fourths of an inch thick. The cement plaster for this work 
is mixed with two parts of sand. In 24 hours the last or finish coat, about 
one-eighth of an inch thick, is put on. It is composed of pure plaster of 
Paris and lime putty. In order to give a white smooth marble like sur- 
face, the brown coat is brought to a smooth surface, and the white coat is 
worked down with a flat wooden trowel called hand float, and a water 
brush to dani]>en the wall. When the walls are to l>e painted a sand finish 
is often used where sand is mixed with the final white coat so as to give 
a rough finish. 

On account of the hard plasters setting more rapidly than the lime 
plasters, it is difficult for a workman familiar with lime work to float a 
hard plaster wall until he has become accustomed to its use. As a result 
lime plaster men with little experience with gypsum plasters nearly 
always condemn them. 

The plaster is applied directly to the brick or stone wall, or it is spread 
over laths made of split white or yellow pine, three to four feet long, one 

210 GYPSUM. 

and one-half inches wide, and one-fourth inch thick. One-quarter inch 
space is left between the lath for the clinch of the plaster. 

In fire proof buildings metallic lath are used, made of woven wire, or 
perforated metal, either plain or galvanized. Expanded metal lath has 
also become very popular and is regarded by many as superipr to the 
other kinds. About 18,000,000 square yards of expanded metal lath are 
used each year in this country. Nearly 10,000,000 square yards were 
used in the construction of the buildings of the Paris Exposition, and 
most of this was furnished from the United States. 

Fig. 44. 

In making the expanded lath a strip of metal seven inches or more 
wide and eight feet long is placed upon a table and a cutter operates on 
it longitudinally cutting and expanding one row of webs at a time. The 
best types of these machines will make 400 to GOO yards a day. In a 
recent method invented by Mr. U. A. Turnbiill of Chicago, a sheet of 
metal seven and one-half inches wide and of the desired length is fed 
into the rolls and cut in a number of short longitudinal overlapping slits. 
The sheet then passes over the expanding rolls, and the metal is stretched 


out in width, enlarging the openings. The machine used in this method 
will make 4,000 to 5,000 yards a day. 

The metal lath is fastened to the studding by iron staples, and the 
clinches formed in the numerous openings give increased firmness to the 
wall. There are numerous patent metal laths now placed on the market. 
Different builders prefer different makes and each thinks he has chosen the 
best. Where the plaster passes through the perforations it spreads out 
and forms a coat on the inside as well as on the outside of the metal, pro- 
tecting it from rust, making strong clinches, almost impossible to break, 
and gives an almost perfect fire proof wall. 

In Michigan most of the calcined gypsum is used for wall plaster, and 
its advantages as set forth in the advertising circulars of the companies 
and supported by the testimonials of prominent architects and builders 
are as follows: 

Its superior tensile strength and hardness. It dries out much more 
rapidly than lime plaster, so that the carpenters can soon follow the 
plasterers; the painter and paper hangers can follow the carpenters in a 
day or two. The entire building can be delivered and occupied from five 
to six weeks sooner than with lime mortar. Coloring compounds can be 
mixed with the material in its preparation for mortar to produce any 
tint desired. Ceiling and walls thoroughly soaked from leaking and un- 
protected roofs have not lieen injured. It attains a high polish and may 
be used for wainscoting as a substitute for marble. It is fire proof and a 
non-conductor of heat and cold, so that changes of temperature do not 
affect the walls which therefore do not chip or crack. The walls being 
dense and hard are vermin proof, making the plaster valuable for hospital 

That these hard plasters are appreciated by the trade is seen from the 
following extract from the American Architect: 

* 4 In this age of improvement it seems strange that men should so 
long have been confined to the use of lime, sand, and hair, for making 
interior walls and ceilings, especially since walls so made have proved 
very weak and unsatisfactory, and many know from sad experience 
what destruction, annoyance and loss ensue, when, from some slight 
cause, its own weight or rottenness, down come ceilings about their 
ears with the inevitable result of damage, dust, and confusion." 

The great objection to the use of cement plaster has been the greater 
expense. It has cost about one-fourth more than the ordinary lime 
plasters, but the greater advantages more than comi>ensatc the first ex- 
pense. It is also said to be noisier, i. e., does not deaden the sound so 

In some localities the careless methods of mixing the materials have 
caused bad results in the work and have caused hard wall plaster to be 

212 GYPSUM. 

looked iii)oii with disfavor. Too much sand will make the sack of plaster 
cover more area, but it weakens it and the same result follows the mixing 
of the old set plasters in the boxes with the new material. 

The directions for the use of these hard plasters are given as follows: 

Use clean, sharp sand and mix thoroughly with the plaster before 
adding the water and do not mix more than can be used in one hour. The 
materials should be mixed in a water-tight box and should never be re- 
mixed after its set has commenced. The box and tools should be cleaned 
after each batch. Brick walls and porous substances should be thor- 
oughly wet before applying the mortar, in order to reach the full strength 
of the materials. Floating should be done with the least possible amount 
of water, as soon as the material begins to stiffen and before it sets. In 
troweling the finish work use as little water as possible to prevent join- 
ings and water streak showing. Use by measure two parts sand to one 
part of fibred plaster. Dry lath should be sprinkled one hour before 
plastering. For the hard white finish, mix one-half lime putty with one- 
half of fibred planter. One ton of gypsum plaster will cover 225 to 250 
yards of surface on wood lath set one-quarter of an inch apart, or will 
cover 225 yards on metal lath, or will float 400 yard. 

The brands of these gypsum plasters made in Michigan are, Plasticou, 
Eagle. Acorn, Hudson Kiver Mills, Green A, Eclipse, Granite, Ivory, 
Adamant, Diamond, Alabaster. 

In many parts of the United States, especially east of the Mississippi 
river, the demand is for a plaster mixed with sand, ready to be mixed 
with water and applied to the walls. In Lower Michigan the two brands 
manufactured are the Adamant and Granite Wall Plaster. The sand is 
thoroughly dried in revolving cylinders or over specially constructed 
stoves, and mixed in Broughton mixers with retarder and plaster of 
Paris, and fiber. 


A high grade hard plaster is now made in Houghton for use in Upper 
Peninsula. The makers, the M. Van Orden Co., claim for it that the consti- 
tuents are very carefully weighed, not measured, very thoroughly mixed, 
and are very uniform, and as a local sand is used in mixing, the freight 
on it is saved. A fat Ohio, so called lire clay, L e., white clay, is used as 
spreader, and it will be seen by Sec. 6, of Chapter VIII, also affects the 

Many Michigan coal underclays might be used for this purpose. 

In order to show the fireproof properties of hard wall plasters, the 
Rock Wall Plaster Co. of Columbus, Ohio, performed the following ex- 
periment in the presence of a party of city and state officials: — 

Four frames were made out of two by four studding, 12 by 18 feet 
square, two of these were wood lathed, one steel lathed, and one covered 


with sheet steel. All hut the last were plastered, coinmon lime plaster 
on one, rook wall plaster on the other two. These were laid on the lires 
in the boiler furnaces in the Hoard of Trade building. 

In less than one and one-half minutes the steel covered frame was burn- 
ing. In seven minutes the lime plastered lath were burning. In '2U min- 
utes there was evidence that the heat had penetratd the rock plaster on 
the wood lath but it had not effected the wood covered with the steel lath. 
At the end of 40 minutes the rock plastered samples were removed and 
found to be charred but not in tlames, while the other two samples were 
practically destroyed. 

The testimony of fire marshals and owners of buildings plastered with 
gypsum plaster, seems to be practically unanimous as the protection of 
such plasters against the spread of tires in such buildings. 

An objection to the use of hard plaster in residences has been that the 
density of the wall makes it a good conductor of sound from one room to 
another, where the partitions are made of the plaster. In order to cor- 
rect this fault various forms of fibred plaster have been invented, known 
as wood fiber, fire pulp, etc. A common material for this purpose is 
wood fiber made on specially constructed machines, and the wood fiber 
is mixed with retarded plaster. One of the very popular pulp plasters 
is made by the Napoleon Pulp Plaster Co., of Napoleon, Ohio. It is a 
mixture of marl, gypsum, fire clay, wood pulp, and fiber, rctarder, and 
lime carbonate. Machinery for this fiber is manufactured by the Wood 
Fil>er Machinery Co. of Sandusky, Ohio. 

The gypsum plasters are sometimes mixed with materials to add to the 
fire-proof qualities. Mixed with asbestos it has been used for plastering 
the inside of stove bowls. Calcined gypsum is mixed with finely ground 
cinders and poured between the iron joists in fireproof buildings. Tempo- 
rary plates are placed above and below the joists giving a smooth under 
surface for the finishing coat of the ceiling of the lower stories, and a 
smooth upper surface on which the tile tloor may be laid. The material 
is claimed to be thirty-live per cent lighter, of twenty-five per cent greater 
strength, and sixty per cent eheajKT than tiling which has long been used 
for this purpose. 

Plaster mixed with asbestos is said to give double strength. This mix- 
ture has been found valuable around steel lieams in fireproof buildings. 
In such buildings a small fire doing but little apparent damage, will some- 
times warp these beams and so twist the structure as to greatly injure its 

§ 4. Manufacture of Hardened Gypsum Plasters. 

When gypsum stone is heated and thrown into a ten per ceut solution 
of alum for a few minutes, and then heated again, the resulting plaster 
on setting is very much harder than the ordinary plaster. 




0.41 0.37 




1.45 1.10 


98.19 98,02 


214 GYPSUM. 

Payen, as stated in the chapter on Technology, in his sixth principle, 
thought the hardening was due to the formation of a double sulphate of 
potash and lime. Landrin analyzed so called alum plasters with the fol- 
lowing results: 

landkin's analyses of alum plasters. 

Elements. cements. 

Carbonate of lime 1.05 

Silica 0.72 

Water 1.48 

Sulphate of lime 90.75 

An examination of these figures shows that the alum cements are of 
great purity, and there is no trace of alumina and potash. Landrin ex- 
plains the hardening of alum plasters as due to the reaction of sulphate 
of alumina and potash on the plaster stone, converting nearly all the 
carbonate of lime into the sulphate, or gypsum. This seems to indicate 
that the French preference for lime plasters is prejudice. 

Landrin placed the crude gypsum in a ten per cent solution of sulphuric 
acid for fifteen minutes and then calcined it, and obtained a plaster of 
good set and hardness. Heat must be applied in sufficient amount to 
drive out all the sulphuric acid and the best temperature was found to 
be between 000° and 700° F. Hydrochloric acid was also tried but with 
poor results. 

By the Greenwood hardening process, the gypsum stone is burned in 
the usual way, then steeped in an 8£ to 10,%' alum solution for some min- 
utes, drained and dried in the air, and again burned at a uniform and con- 
stant temperature carried to dull redness but not beyond. 

The earlier patents of Keene and later of Keating called for a mixture 
of plaster of Paris with one part borax, one part cream of tartar, and 
eighteen parts of water. This mixture was burned at a low red heat for 
six hours. 

Borax alone produced good results. One volume of saturated solution 
of borax and twelve parts of water made a plaster which set in one- 
fourth hour; with eight volumes of water, it set in one hour; and with 
four volumes of water, the set was delayed several hours. This cement 
is known under the name of Parian cement. These cements were liable 
to effloresce, throwing off paint, and this is remedied by neutralizing the 

Keaur and Knop made silicated plaster used for sponging plaster casts, 
giving them increased hardness. To a potash lye made by adding one 
part potash to five parts water, some milk whey is added as free as pos- 
sible of fatty matter. Four parts of this lye are mixed with a syrupy 


solution of potassium silicate. Sulphur in the whey may make dark 
stains which will disappear when dry. 

A German method of making a hard plaster is to add to plaster of Paris, 
two to four per cent of pulverized eibisch roots and mix with 40# water. 
This will harden in an hour. Eight per cent solution will make a still 
harder solution. 

Martins' cement is a mixture of plaster of Paris and (commercial 
K 2 C0 3 ) pearl ash, instead of borax, and produces a fatter cement. Kuhl- 
man's method was to harden the plaster with a solution of water glass, 
but it is not always satisfactory. Blashfield used lime water to which 
some zinc sulphate is added. 

Heinemann, in Hanover, under patent issued July, 1S83, heated the 
crude gypsum rock and placed it in a lime chloride solution, then im- 
mersed it in a magnesia sulphate solution, and finally treated with lime 
and tannin solution, and dried the product. The finer varieties of white 
plaster are sometimes called Marezzo marble or white Portland cement. 

Magaud's cement is made by treating the gypsum with a solution of 
sulphate of zinc, sulphate of iron, or sulphate of copper. 

M. Julke communicated to the French Academy of Sciences in 1885 a 
new method for hardening plaster. By this method six parts of the best 
quality of gypsuni plaster and one part of fat lime recently slaked and 
finely sifted are mixed. This is used in ordinary plaster. When it is 
dry the mass is soaked in a solution of some sulphate whose base may be 
precipitated by lime forming in insoluble precipitate. Among the most 
convenient sulphates are iron and zinc. The lime in the pores of the plaster 
decomposes the sulphate producing two insoluble bodies, sulphate of lime 
and oxide of lime which fill the pores giving the dense hard plaster. With 
zinc sulphate the object remains white, while with iron it is at first 
greenish and on drying it takes a reddish color. The iron surfaced casts 
have a strength twenty times greater than in the ordinary plaster casts. 

Landrin found that lime had great influence in gypsum plasters. By 
mixing lime with the plasters in different proportions he obtained plaster 
which set regularly, became hard and took a high polish. He states that 
it is better not to use over ten per cent of lime. Laudrin's explanation 
for this change is that the lime in contact with water sets free heat, 
which evaporates the quantity of water not needed to bring the hydrated 
plaster back to its original gypsum state. The carbonic acid of the air 
then carbonates, little by little, the excess of lime in the plaster, giving 
increased solidity and hardness to the plaster. 

General Scott invented a mixture sold under the name of selenitic 
mortar which consists of Portland cement, with plaster of Paris or green 
copperas (ferrous sulphate). This hastened the set, and the invention 
attracted much attention some years ago, but modern experience is 
against this addition where great strength is required. 

216 GYPSUM. 

Scagliolia is a mixture of plaster of Paris, retarder, and coloring sub- 
stances and is used to imitate various kinds of marble and ornamental 
stones. The original mixture contained numerous splinters (scagliole) 
of marble which has given the name. 

In the Pantheon of Paris 1 the surface of the dome was dried by large 
braziers to remove all moisture. A mixture of one part yellow wax, three 
parts oil, in which one-tenth of the whole weight of litharge had been 
mixed before melting, was then applied at a temperature of 212° F. It 
was laid on with a brush until the stone would absorb no more. The 
paintings of M. Gros were then put on and have stood 20 years without 
trace of cracking or change on this plastered wall. A mixture of one 
part oil with one-tenth of its weight of litharge and two or three parts 
of resin is sometimes used in this way. 

Roman cement, sometimes cited as a variety of gypsum cement was 
according to Parker's original English patents a hydraulic lime made 
from lime carbonate nodules found in clay. 

§ 5. Gypsum Paints. 

The finely ground gypsum is calcined and carefully bolted, then set 
with water in the form of oblong prisms. These after thoroughly drying 
in the open air, are reground and the resulting powder is sold as Mich- 
igan whiting, and used in a variety of ways. The true whiting used with 
linseed oil in the manufacture of putty is carbonate of lime, and the 
Michigan whiting has been tried as a substitute but does not work satis- 

The Michigan whiting is used as paper filler. The bleached pulp in the 
manufacture of paper is drawn out in fine fibers on the beater rolls and 
is then loaded with some mineral material consisting usually of china 
clay or fine gypsum. When this is added in moderate quantity it closes 
up the pores of the fibers and enables the paper to take a better finish. 
It is used especially in writing and printing papers. 

§ G. Selenitic Lime. 

Selenitic lime 2 or cement is an artificial mixture of gray chalk or other 
similar lime and a proportion of plaster of Paris. In one method lightly 
calcined gray chalk lime is reheated to bright redness in shallow kilns 
having perforated floors, under which are placed pots of sulphur. The 
heat igniting the sulphur produced fumes of sulphurous acid which rise 
and form a coating probably of sulphate. 

In another the sulphuric acid is sprinkled on the calcined lime, or 
plaster of Paris is mixed with the ground lime. In one method four 
pounds of plaster of Paris is mixed in one half pail of water, to be added 
to one bushel lime in a mortar mixing mill, with sufficient water to make 

iHurnett. Limes. CemeDtF, Mortars, London, pp. 97-112: 1892. 
SHeaih. A Manual of Lime and Cement, London, pp. 29. 30. 

(ieologicitl Survey of Michigan. 

Vol. IX Part II Piute XXVI. 



a creamy paste. These limes set rapidly and soon become hard but they 
are not commonly used, and cannot be used where they are exposed to 
the weather. 

§ 7. Alabastine. 

Alabastine, made at Grand Rapids, is often called cold water paint. 
Jn its preparation the pure blocks of gypsum rock are selected, ground, 
calcined, and then reground to the finest powder. This superfine gypsum 
flour is mixed with metallic colors and sold in packages to be used for 
tinting and frescoing interior walls. Five pounds of the material will 
cover fifty square yards of plain tinting on a smooth non-porus wall. 
It can be used over any solid surface, such as plaster, wood ceiling, brick, 
or canvass, and is applied with an ordinary wall brush. It does not Hake 
or scale off, and hardens like the wall on which it is placed and so can be 
applied coat over coat. 

In mixing the material two and one-half measures of Alabastine are 
added to one measure of cold water and stirred thoroughly and should 
be used within five hours. It is flowed on the wall heavily and brushed 
out to the proper thinness. It is claimed to cover 50 to 100# more surface 
than kalsomine made from lime and glue. It can be made in any tint or 
combination of tints to match carpets or draperies. Forty tints can be 
made from three colors, red, yellow, and blue, mixed with white ala- 
bastine. See Plate XXV. 

The material is used with a free hand relief machine in making raised 
designs for borders of rooms in any variety of patterns. It can be used 
to imitate ivory, embossed leather, antique metal, tiling, etc. It is used 
in a pneumatic machine for whitening the interior walls of factories and 

§ 8. Lieno. 

Another preparation of line ground gypsum and metallic colors is made 
by the United States Gypsum Co., and sold under the name of Lieno, a 
word formed by reversing the letters of the inventor's name, Mr. O'Xeil. 
This material is made in shades somewhat like Alabastine, and it is used 
in the same way for tinting walls. The company make a special feature 
of the use of Lieno for relief work. For this purpose two parts of the 
material are used with one part of warm water. It is sold in live pound 
packages, 100 pound drums, and 300 pound barrels. 

For relief work the Lieno is put on the walls with a Lieno free hand 
relief machine made by the company and shown in Figure 45. This ma- 
chine is made of brass, nickel plated, and has two cylinders for holding 
the mixture, so that the helper can be filling one while the operator is 
using the other. Pressure is applied by a ratchet and lever which forces 
the material through the tube. The machine should be held in the right 

218 GYPSUM. 

hand and steadied with the left. The tube should rest lightly against the 
surface and at an angle to allow the material to flow out. A series of 
tubes are prepared through which the substance flows to the surface 
producing the various widths and shapes of lines and scrolls. A variety 
of designs are made from a few principal patterns grouped together in 
different ways. After the designs are made on the wall, they may be 
colored for any tint desired, or the coloring material can be used in 
making the relief. 

These gypsum paints are now used in all parts of the country and have 
become very popular for interior decorations. An artistic painter can 
make original designs, giving* variety and harmony of color. The in- 
experienced can secure patterns and careful directions from the com- 

§ 9. Trippolite. 

In the building markets of Vienna a new gypsum mixture has appeared 
in recent years under the name of Trippolite, which has a gray color and 
contains mainly calcined gypsum and four or five per cent of powdered 
carbon. Trippolite is said to have double the strength of ordinary plaster 
and to remain under water without disintegration and can be used as a 
hydraulic mortar. Two analyses of this substance are here given: 1 

A. B. 

Sand 1.16 1.40 

Soluble silica 1.35 

Sulphate of lime 74.98 74.90 

Sulphate of magnesia 0.11 

Carbonate of lime 6.44 4.61 

Carbonate of magnesia 1.84 4.15 

Iron oxide 0.55 0.54 

Alumina, potash, soda trace trace 

Carbon 11.60 11.44 

Water 3.00 2.86 

99.68 101.25 

§ 10. Pottery Moulds. 

Plaster of Paris is used for the manufacture of moulds for various 
pottery designs, and this method of making pottery is taking the place of 
hand turning. In many of our American potteries, jugs, vases, etc., are 
made in these moulds. 

In England 30,000 to 40,000 tons of plaster are used for this purpose 
annually, especially in Staffordshire potteries, and gypsum rock is often 
called in that section the potters stone. 

These moulds are used on a jolly wheel made like an ordinary turner's 
wheel, but provided with a hollow head which can receive moulds of 

• Handbuch der Chemischen Technologic Bolley and Birnbaum, Band ft. p. 360: 1885. 


various kinds. Each jolly wheel is provided with from 1,000 to 3,000 
moulds. In a large pottery where a wheel is run all day on one kind of 
ware and each mould used twice, it would require 1,200 to 1,800 moulds 
for this one kind of pattern. The porous gypsum mould permits the 
evaporation of moisture from the clay while the surface of the ware is 
not exposed, thus avoiding any danger from strong drafts which are 
sometimes destructive in hand turned ware placed on open shelves. 

§ 11. Plate Glass Polishing. 

After the plates of heavy glass in the plate glass manufacture come 
from the kilns or leers, it is ground smooth under revolving brushes 
charged with emery flour. In order to hold the plate firmly and remove 
all strain, large circular tables 24V-» feet in diameter and eight to ten 
inches thick with a weight of GG,000 pounds are covered with a coat of 
plaster of Paris finely ground and free from all traces of grit. In this * ;^T*" 

plaster the glass plates are imbedded. When the first side has been 
polished, the plaster is broken off at the edges and the plates removed. 
The table is then thoroughly cleaned and coated again with plaster and 
the smooth side of the plate imbedded, while the other side is polished. 

In many factories the gypsum is oalciucd in kettles at the factory and 
the old set plaster is recalcined and mixed with the new for the first 
polishing, but for the second side new plaster must be used to avoid any 
danger of grit coming in contact with the polished surface. 

It requires 2,200 pounds of plaster for 1,000 square feet of plate glass. 
The Michigan gypsum from Alabaster is held in high favor for this use 
on account of its purity, and most of the plaster used comes from this 
mine. In the plate glass factories of the United States, 40,000 tons of 
plaster are used annually. 

At Saginaw is located a modern plate glass works with a capacity of 
1,000,000 feet per year, and the Alabaster superfine plaster is used in the 
polishing of the plates. 

§ 12. Plaster Kelief Work. 

A plaster industry which has been in existence from an early day came 
into special prominence at the World's Fair. The buildings at the Chi- 
cago fair were const ruetcd on the outside of gypsum plaster and liber, 
making a composition known as staff. Large quantities of gypsum plaster 
were consumed in the construction of these temporary buildings and orna- 
ments. In the same way large quantities of this stuff were used 
at St. Louis for the fair buildings. Most of tin? staff plaster at Chicago 
came from Michigan, and most of the staff at St. Louis is shipj>ed from 
this State. 

Staff is especially adapted for decorative const met ion and remains in 
good condition for a considerable length of time in outside work, but 



the elements of the air will in a few years cause it to disintegrate and 
crumble, if not protected by some water-proof covering. 

The use for interior relief and art decorations has increased to a re- 
markable extent since the Chicago exposition. The group figures and 
mouldings in American theaters, public halls, and even private resi- 
dences, are now made from staff. 

In this manufacture, the design is modelled by the artist, in clay and 
then a mould is made of gelatin glue. A mixture of stearic acid and coal 
oil is used to oil the mould and prevent the cast from adhering. Into 
this mould is thrown a mixture of plaster of Paris and fiber, and finally 
on the outer surface pure plaster. The whole is worked into the mould 
with the fingers, or in large designs it is pressed into the proper form by 
means of a wooden die or scraper with its edge cut to the proper shape. 
The plaster is allowed to set and is then removed from the mould. 

Fig. 45. Gypsum boards used in making walls 
where few uprights are used. 

Large pieces are moulded over a steel frame which can be fastened in 
place by screws or staples. These designs are left in pure white or are 
painted in desire<r tints. Before painting they are coated with shellac. 
Large factories for this work are located in Detroit, Chicago, and other 

§ 13. Manufacture of Floor Blocks. , 

Gypsum plaster is sometimes mixed with sawdust and moulded into 
blocks which are then readily nailed to the wall for finish. The Macko- 
lite Fire Proof Co., of Chicago, is engaged in the manufacture of fire- 
proof blocks for floors, walls, and ceilings, made from the Michigan 
plaster. The Grand Kapids Plaster Co., have recently started the manu- 
facture of these boards. 

The manufacture of these plaster building blocks for interior work is 



a prominent feature in the (Senium gypsum industry. (Bee Figures 45- 
4(5.) These boards or blocks ("schilfbretter") are described in detail in 
the Thonindustrie, page 1089, 181)0. Another account is given by Mr. 
Wilder of the Iowa Geological Survey 1 report, from which source the 
following account is taken: 



4ft Gypsum boards fastened to narrow wooden strips in iron uprights. 
Such a wall Is practically tire proof. 

"Calcined plaster is mixed with water and a certain amount of saw 
dust. On an iron table with a heavy iron top are laid iron strips, which 
have a thickness equal to that intended for the gypsum boards. The space 
enclosed by these* strips also determines the length and breadth of the 
board. Within this space are scattered excelsior, jute, and rushes, and 
over these is poured the gypsum, water and sawdust mixture. The nishes 
and excelsior are carefully worked into the middle of the mass by hand. 
An iron bar is drawn over the top of the strips, leaving the surface of the 
mass either smooth or ridged. It is allowed to stand about five minutes, 
and then the iron table on which the mass rests is struck vigorously two 
or three times with a heavy mallet. This loosens the gypsum board from 

iVol. XIL 

222 GYPSUM. 

the iron plate and strips. A workman takes it on his shoulder and carries 
it to an open shed where it stands on end until dried by natural heat. 
The length of time required for drying depends wholly on the atmos- 
pheric conditions. Artificial heat for drying gypsum boards has proven 
very unsatisfactory, as the boards so dried crumble readily on exposure 
to the air. The weight of gypsum boards 2.5 centimeters thick is about 
50 pounds per square meter, and for boards eight centimeters thick about 
120 pounds." 

§ 14. Gypsum as a Basis for Portland Cement, with Sulphuric Acid 
as a By-Product. 

Attempts have been made to manufacture Portland cement and 
sulphuric acid from gypsum. It is claimed that the process will cost 
about the same as in the ordinary methods of making cement and there 
4BgX will be the sulphuric acid in addition for profit. One or two patents have 
been issued for this work, but the process has not gone much beyond the 
experimental stage. 

Patent number 342,785 was issued in I860 to Uriah Cummings of Buf- 
falo, New York, 1 which gives the following method for this manufacture: 

"In practicing my invention, I mix together gypsum or sulphate of 
lime and clay in the proportion of about 1,266 pounds of gypsum to 400 
pounds of clay. I prefer to pulverize the gypsum and dry the clay and 
pulverize the same, then intimately mix the pulverized gypsum and 
clay and add a small quantity of water, and mould the mixture into 
blocks substantially in the manner practiced in making Portland cement 
from carbonate of lime and clay by the well known dry process. I then 
subject this mixture to calcination in a suitable kiln. At the high de- 
gree of heat which is maintained during the process of calcination the 
silicic acid contained in the clay expels the sulphuric acid contained in 
the sulphate of lime and combines with the lime and alumina and 
produces therewith silicates of lime and alumina, which, upon being re- 
duced to powder, are in every particular a hydraulic or Portland cement. 
The sulphuric acid is expelled during this process of calcination either 
in the form of vapor, or it is decomposed and forms sulphurous acid 
and oxygen; or perhaps the escaping gas is a mixture of vaporized sul- 
phuric acid, sulphurous acid and oxygen, according to the degree of 
heat which is maintained during the process of calcination, and which 
may vary somewhat a1 different times, owing to differences in quantity 
and quality of the fuel employed, strength of draft, etc. The gases 
escaping during the process of calcination are cooled in suitable cham- 
bers or passages lined with lead, in which the sulphuric acid is con- 
densed and collected. The sulphurous acid, if any, is converted into sul- 
phuric acid in 1 lie ordinary manner by means of steam and nitric acid. 
The sulphuric acid so obtained is then concentrated or further treated 
in any usual manner practiced in the manufacture of sulphuric acid. 
The mixture of gypsum and clay above specified produces about '711 

'Iowa (ieolopi Mil Survey. Vol. XII. pp. 15M5Q. 


pounds of hydraulic or Portland cement and 580 pounds of sulphuric 
acid from every 1,660 pounds of the mixture, the balance being moisture 
which is expelled. The cost of the sulphate of lime is about the same 
as that of the carbonate of lime and the cost of manufacturing hydraulic 
or Portland cement by this improved method is about the same as that 
of the old method in which carbonate of lime is employed; but the sul- 
phuric acid which is obtained in my improved method is valuable, and 
the value which it represents materially reduces the cost of the cement. 

"In practicing this invention, any suitable kiln in which the process 
of calcining can be carried out may be employed, and any ordinary 
apparatus may be used for recovering the sulphuric acid. 

"The condensing and covering chambers are connected with the top 
of the kiln by a suitable flue, and the waste gases are discharged from 
the condensing or converting chambers by a stack or chimney or suit- 
able fan which maintains the proper draft through the kiln and the 

"The proportions herein specified are found to be well calculated to 
produce the desired results; but they may be varied in accordance with 
the nature of the gypsum rock and clay employed within certain limits 
without changing the general results. If the proportion of clay used 
be too great, the cement will be of an inferior quality but the sulphuric 
acid contained in the sulphate of lime will be driven off and recovered. 
If any excess of gypsum be used die lime contained therein is in excess 
of the true combining proportions with the silicic acid and the sulphuric 
acid will not be driven off and the resulting cement will be inferior in 
quality by reason of the presence of sulphate of lime, although a small 
percentage of the latter my be present without exerting any specially 
deleterious influence." 

According to the method of P. Van Denberg of Ruffalo, New York, 
under patent number 642,390, issued in 1000, sulphuric acid is made 
from gypsum by subjecting the gypsum to heat and electrolysis produced 
by an electric current within a furnace and applied to the material while 
molten. In the presence of an excess of free oxygen, sulphur oxide is 
formed which is hydrated later, yielding sulphuric acid. 



In order to show the importance of the gypsum industry in the world, 
and especially in the State of Michigan, the following tables are pre- 
sented. The tables have been taken from the reports on Mineral Ite- 

1 1 1 



1 1 1 

— -j 

— p . 




. J 

1 I 

1 VL__i 



8 1 I -- 

_. i 'i 



' ( ' 

i ^^ 






~." " 

. L^-^Z. 

I \/ 



■ [' 1 l i 

' ' "i i — ^» 


i s 

*^*> t 



Fig 47. Total Production of Gypsum. 

Geological Survey of Michigan. 

Vol. IX Part II Plate XXVII. 

: . -. 

' \ 

w 3 

Y\ i 













V 7 






1 -a 


r >5 



' *• 





sources published by the United states Geological Survey, and they are 
taken mainly from the 1901 report. 

In the table of the Michigan production, the quantity of gypsum mined 
from 1867 to 1899 inclusive, is taken from Lawton's statistics as published 
in the government reports referred to above ; but the amount of rock cal- 

Pig. 48. Land Plaster Production. 

cined into plaster, and the values were computed from these tables by 
the writer, taking estimated values for these years. The difference in the 
source of the statistics brings in a discrepancy between the values in 1889 
and 1890. 

A comparative study of these tables of statistics and of the diagrams 
accompanying them, brings out some interesting conclusions. From 



table I, it is seen that France has held first rank in the production of 
gypsum in the world during the years 1893 to 1901, and the United States 
has held second rank. In 1894 France produced over six times as much 
gypsum as the United States, and in 1900 France only produced three 
times as mtich as the United States. 

1 885 

1 892 

1 893 

Fig. 49. Gypsum Calcined into Plaster. 

Table III and Figure 47 show that the production of gypsum in the 
United States has increased in 20 years from 1880 to 1900 from 90,000 to 
594,402 tons or 560 per cent. The production of gypsum in 1901 was the 
greatest recorded in the United States. The production in 1900 was the 
greatest recorded up to that year in the United States, Canada, Germany, 
Cyprus; but was less than the preceding year in Great Britian, Algeria, 
and India. 

The imports of crude gypsum into the United States, which come al- 

i ■ 1 ■ -T 1 \ J 

'r ' r ' i ' i i 

1 ■ T- 1" f L_J 

to / 
<-> / 
o / 













most entirely from Canada, were greater in 1901 than in any other year. 
The total amount of gypsum used in the United States in 1001, from these 
tables was 897,909 tons, with a value of 91,904,163. 

In 1890, 56,525 tons of gypsum were ground into land plaster, and 
107,728 tons were calcined, or about one-third used for land plaster, and 
two-thirds used for plaster of Paris and like products. Tn 1901, 65,698 
tons were ground into land plaster, and 521,292 tons calcined, or about 
one-ninth used for land plaster, and eight-ninths for calcined plasters. 


From the study of Table V, it is seen that the total production of gyp- 
sum in Michigan since the beginning of the industry is 2,827,793 tons, 
one-half of which was converted into land plaster and one-half into cal- 
cined plaster. Before 1868 about one-tenth of the product was calcined 
and nine-tenths was ground for land plaster. 

In 1901, out of a total production of 185,150 tons, 129,256 tons were 
calcined or 69 per cent; and about 5 per cent was ground into land 
plaster, the remaining portion was sold crude. 

The total value of gypsum quarried since beginning of the industry in 
Michigan is ov£r 910,000,000. 

A study of the diagrams. Figures AS and 49, shows that production of 
calcined gypsum has steadily increased and the land plaster production 
has decreased. A marked increase in calcined plaster is shown in the 
years 1892 and 1893 during the World's Fair, the buildings of this exposi- 
tion requiring large quantities of plaster in their construction. 













rids Production of Gypsum, from 1803 to 1902 inclusive. 

United States. 

Great Britain. 








































































TABLE I.— Continued. 
World's Production of Gypsum, from 1803 to 1902 inclusive. 

Prance. Algeria. Germany. 

Quantity, Quantity, Quantity, 

Year. tons. Value. tons. Value. tons. Value. 


1894 1,693,831 $2,891,365 36,355 $114,900 

1895 „ 2,175,448 3,392,768 50,127 133,226 23,994 $11,040 

1896 1,866,498 2,661.200 41,350 114,361 31,736 14,598 

1897 1,845,874 2,673,033 40,510 109,648 28,821 13,228 

1898 1,931,712 2,777,816 41,156 110,660 28,315 13,136 

1899 1,802,812 2,641,020 , 44,037 117,895 32,760 19,660 

1900 1,761,835 2,772,221 41,446 139,190 39,103 17,199 

1901 2,182,229 3,449,747 38,955 132,286 35,013 23,139 




















Gypsum Production in the United States since 1889, by States. 



California ...... 




New York 


South Dakota.. 


Other states (c) 







17,332 $94,235 20,250 $72,457 40,217 $161,322 
















































' 28,207 

Totals 267,769 $764,118 182,995 $574,523 208,126 $62,051 256,259 $695,482 



California — 

Colorado ' 


Michigan — 
New York . . . 


South Dakota. 



Other states (c) 

1898 (a) 
Tons. Value. 





124 590 







. (d) 


































' 43,710 















253,615 $696,615 239,312 $761,719 261,685 $892,245 195,553 $583,186 




Gypsum Production In the United States since 188J, by States. 




Kansas , 



New York 


South Dakota . 



Other states.. 







short tons. 


j 83,913 








short tons. 

















23,388 11,480 
101,586 108,585 


Totals 241,861 $774,626 291,638 $755,280 486,235 $1,297,080 

States. short tons. 

California 3,280 

Colorado 5,812 

for"! 313,858 

Michigan 129,654 

New York 58,890 


South Dakota. 


Virginia! !!."."!'.!."!!."."!!!. ".".'!!!".".". !!!!!."! ii,946 

Other states 71,028 







short tons. 











Totals 594,462 $1,627,203 659,659 $1,577,493 

Production of Gypsum in the United States, by Years. 


Year. tons. Value. 

1902 816,478 $2,089,341 

1901 633,791 1,506,641 

1900 594,462 1,627,203 

1899 486,235 1,287,080 

1898 291,638 755,280 

1887 286, 982 755,280 

1896 224,254 573,344 

1895 265,593 797,447 

1894 239,312 761,719 

1893 253,615 666,615 

1892 256,259 695,492 

1891 208,126 628,051 



1890 182,995 

1889 267,769 

1888 110,000 

1887 95,000 

1886 95,250 

1885 90,405 

1884 90,000 

1883 90,000 

1882 100,000 

1881 85,000 

1880 90,000 



230 GYPSUM. 


Gypsum imported into the United States form 1807 to 1902. inclusive. 

Calcined. Unground. 

Year ending quantity. Quantity, Value of Total 

June 80. long tons. Value. long tons. Value. Plaster of Paris. Value. 

1867 $29,895 97,951 $95,386 $125,281 

1868 33,988 87,694 80,362 114.350 

1869 52,238 137,039 133,430 $844 186,512 

1870 46,872 107,237 100,416, 1,432 148,720 

1871 64,465 100,400 88,256 1,292 154,013 

1872 66,418 95,339 99,902 2,553 168,873 

1873 35,628 118,926 122,495 7,336 165,459 

1874 36,410 123,717 130.172 4,319 170,901 

1875 52.155 93,772 115,664 3,277 171,096 

1876 47,588 139,713 127,084 4,398 179,070 

1877 49,445 97,656 105,629 7,843 162,917 

1878 33,496 89,239 100,102 6,989 140,587 

1879 18,339 96,963 99,027 8.176 125,542 

1880 17,074 120.327 120,642 12,693 150,409 

18bl 24,915 128,607 128,107 18,702 171.724 

1882 5,737 53,478 128,382 127,067 20.377 200,922 

188:} 4,291 44,118 157,851 152,982 21,869 218,969 

1884 4,996 42,904 166,310 168,000 210.904 

1885 6.418 W.208 117,161 119,544 173,752 

1886 5,911 37,642 122,270 115,696 153,338 

1887 4,814 37,736 146,708 162,154 199,890 

Dec. 31. U~ ' E?5 

1888 3,340 20,764 156,697 170,023 190,787 

1889 5,466 40,291 170,965 179,849 220,140 

1890 7,568 55,250 171,289 174,609 229,859 

1891 9.560 97,316 110,257 129,003 226,319 

1892 6,832 75,608 181,104 232.403 308.011 

1893 3,363 31,670 164,300 190,254 211,924 

1894 2,027 16,823 162,500 179,237 196,060 

1895 3.295 21,526 192,549 215.705 10,352 247,583 

1896 3,292 21,982 180,269 193,544 11,722 227,248 

1897 2,664 17,028 163,201 178,686 16,715 212,429 

1898 2,973 18,501 166,066 181,364 40,979 240,844 

1899 3,265 19,250 196,579 220,603 58,073 297,926 

1900 3,109 19,179 209,881 229,878 66,473 315,530 

1901 3,106 19,627 235,204 238,440 68,603 326,670 

1902 3,647 23,225 305,367 284,942 52,533 360,700 




Statistical table showing product on of gypsum in Michigan by years. 

Gvpsum Total 


1894. . 
1878. . 
1875. . 



Land planter, 

calcined into 





plaster, tons. 





















































































28,184 - 















34 ,374 





























































Total 1,035,795 1,436,850 336,238 2,827,793 $9,986,420 



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Vol. IX Part II Piute XXVIH 



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Natural History, pp. 75-137, by C. N. Gould : 1901-02. 
PARIS GYPSUM— LaCroix; Paris Museum Reports: 1897. 

La Grande Encyclopedic; Article Pl&tre; Vol. XXVI, p. 1078. 
Lapparent, G^ologie, pp. 135, 320, 321, 336-338, 692, 988, 993, 
1026, 1035, 1039, 1474. 

Le gypse de Paris et les min£raux qui l'acconipagnent ; nou- 
velles archives du museum, Vol. IX, (Paris) pp.201-296, 8 plates, 
by A. Lacroix : 1897. 

Nouveau Dictionnaire des Sciences et de leurs Applications 
(Paris), pp. 498, 499: 1900. 

On the peculiar and distributive characters of the gypsum 
found near Paris, and its preparation and application as a 
plaster, by Geo. R. Burnell; The Civil Engineer and Architect's 
Journal (London), Vol. XIII, p. 183-189: 1850. 
PAYEN— Traits de Chimie Industrielle: 1830. 

Uber Gypsbrennen; Bull, des Sciences technologiques. Vol. 
XIII, p. 246. 
PENNSYLVANIA — Gypsum in; Geol. Survev of Penn., Summarv Final 

Report, Vol. II, pp. 913-915 : 1892. 
PERIN — Dosage des incruits et des surcuits dans ]<» Plait re de Paris des 

fours cule^s; Comptes Rendu, Vol. CXXXI, pp. 950-952: 1900. 
PFAFF — Sur les boracites et le succin qui se trouvent dans le gypse 
de Segeberg (Holstein) ; Annales de Chimie, Vol LXXX1X, p. 
199 : 1814. 
PLASTER ANCIENT — Ein plastischen Gypsmortel aus alter Zeit., 

Haarmann's Zeitung, Vol. XLIV, pp. 62, 63. 
PLASTER OF PARIS — On the improved mode of making plaster of 
Paris (translated from Dictionnairie Technologique) : Journal 
of Franklin Institute, Vol X, pp. 262-264 : 1830. 
PLASTERING METHODS, ETC.— American Builder, Sept. IS, 1897; 
Jan. 23, 1897. American Architect, Aug., 1896. 

238 OVPSUM. 

Canadian Architect, Feb., 1899. 

Plain and decorative plastering, by Wm, Millar (London), 604 
pages: 1897. 
PLASTER OF PARIS— Method of calcining and boiling of plaster of 
Paris; Grand Rapids Democrat, Michigan, Nov. (>, 1892. 
"Manufacture of; Eel. Eng., Vol. V, p. 423. 
Scientific American Suppl., Vol. XXXI, p. 12, 685. 
Scientific American (new series), Vol. XXIX, p. 399. 
PORTLAND CEMENT— Use of gypsum in; Ciments et Ohaux hydrauli- 

ques (Paris), by Candlot, pp. 325-335: 1898. 
PORTO RICO— Gypsum in; U. S. Geol. Survev, 20th Annual Report, part 

VI Cont, p. 744 : 1899. 
PRODUCTION OF GYPSUM— In Oil, Paint & Drug Reporter, Vol. LVI, 
p. 26, (quotation from U. S. Geol. Survey Reports). 

See the various reports on Mineral Statistics, in the volumes 
of the U. S. Geol. Survey Reports. 
RED RIVER — (Of Louisiana, Texas) ; Marcy's Exploration; see Marcy. 
REDGRAVE — Calcareous Cements, their nature and uses : 1895. 
ROSE, H. — On the solubility of gypsum; Poggendorff Annalen. Vol. 

XCIII, p. 606. 
ROSOY— Le Platre; Gazette des Architect es, Vol. XIX, p. 195. 
SELENITIC LIMES — An account of the influence of gypsum on hydrau- 
lic limes; Van Nostrand Eng. Magazine, Vol. VII, p. 542. 

A Manual of Lime and Cement, by Heath ( London ) , pp. 29, 30. 
SET OF PLASTER— M^chanisme de la prise du pl&tre, bv Chatelier; 
Comptes Rendu, Vol. XCVI, p. 715; Bull. Mustfe, (Paris), Vol. 
LXXXIII, p. 108. 

M£chanisme de la prise du plAtre, bv Daubrtfe; Revue indus- 
trielle, Vol. XIV, p. 145. 
SHERWIN — Theories of origin of gvpsum ; Trans. Kans. Acad. Science, 

Vol. XVIII, pp. 85-88 : 1903* 
SOCQUET — Des Efflorescences de sulfate de Magn^sie observes sur les 
Carrteres de Montmartre; Annales de Chimie (2nd series), Vol. 
XLII, pp. 51-64. 
SOLUBILITY OF GYPSUM— Amer. Cheni. Jour., Vol. II, p. 30, by Mc- 
Caleb: 1889. 

Berichte des Deutsch. Chem. Gesellschaft, p. 330:1877. 
Jahresbericht der Chem. Technologie, by Wagner, p. 727: 1877. 
In aqueous solutions of sodium chloride, by Dr. Frank Cam- 
eron; Journal of Physical Chem., Vol. V, pp. 556-570: 1901. 

Lecoq de Boisbaudran, note sur la solubility du gypse dans 
Peau; Annales de Chimie (series 5), Vol. II, p. 477. 
H. Rose; Poggendorff Annalen, Vol. XCIII. p. G06. 
Loslichkeit von Gvps in Wasser; Zeitschrift fur Chemie, p. 

Solubility of gypsum in aqueous solutions of certain electro- 
lytes, by Cameron and Seidell; Jour, of Phys. Chem., Vol. V, 
: number 9, pp. 643-655: 1901. 

[' Storer, Dictionary of Solubilities. 

SOUTH AMERICA — Geology of South America, by Darwin (see article 
in index). 


SOUTH DAKOTA— Gypsuin in, and analysis of Hot Springs gypsum; U. 

8. Geological Survey Annual Report, Vol. XXI, part IV, p. 585. 
;SPERENBERG— Gypsindustrie in; Haarman's Zeitschrift fur Bau- 

handwerker (Halle), Vol. XLII1, pp. 11, 12. 
STEVENSON — Gypsum in Holston Valley, Virginia; Proc. Amer. Philos. 

Soc. XXII, pp. 154-161 : 1884. 
STORER — Determination of water and sulphuric acid in gypsum ; Chem- 
ical News, Vol. XXII, p. 99. 
STUCCO— Eel. Eng., Vol. XVI, p. 368. 

SUGAR— Effect on cement ; Engineering News, Dec. 24, 1887. 
TESTS. PHYSICAL ON GYPSUM— Iowa Geol. Survey, Vol. XII, pp. 

224-235, by Marston : 1902. 

In Wyoming, by Slosson 10th Annual Report of Univ. of Wy- 
oming, pp. 9-17 : 1900. 
TEXAS — Geological Survev of Texas, 1st. Annual Report, pp. 19, 30, 

42, 43, 44, 46, 48, 52, 53, 73, 99, 100, 123, 188, 189, 193, 

197, 205 : 1889. 

Second Annual Report, pp. 410, 447, 457, 458, 459, 700. 
THORPE— A Dictionary of Applied Chemistry, Vol. 1, article on 

THURINGIAN FOREST— Gvpsum in; Quart. Jour. Geol. Soc, Vol. XI, 

p. 425. 
TRIPPOLITE — Borchert, Illustrirte Zeitung fiir Blechindustrie ; 

Deutsche Topfer und Zeiglerzeitung, Vol. XIV, p. 322. 
Kalk, Gyps, und Portland Cement, Tarnawski (Vienna), p. 

TUSCANY— Gypsum in; Quart. Jour. Geol. Soc., Vol. I, pp. 280, et seq.: 


Bull. 223:1904. 
VIRGINIA— Resources of Southwest Virginia, by Boyd, pp. 104-108: 

1881; U. S. Geol. Survey, Bull. 213, pp. 406-416: 1903. 

In Holston Valley; Trans. Am. Inst. Min. Eng., Vol. V, p. 

91; Vol. XXI, p. 28; Proc. Amer. Philos. Soc, Vol. XXII, pp. 

154-161 : 1884. 

In Mesozoic; Trans. Am. Inst. Min. Eng., Vol. VI, p. 244. 
WILDER, FRANK A. — On gypsum deposits in Iowa; Iowa Geol. Sur- 
vey, Vol. XII, pp. 195-223: 1902. 

The gypsum industry of Germany ; Mime report, pp. 195-223. 
Present and future of American gypsum industrv ; Eng. & Min. 

Journal, Vol. LXX1V, number 9. pp. 276-278: 1902. 
WEBER, MARTIN— Die Kunst des Bildformers und Gipsgiessers : 1896. 
WILKINSON — The teehnologv of cement plaster; Trans. Am. Inst. Min. 

Eng.; July, 1897. 
WILLIAMS — See New York gypsum deposits. 
WYOMING — The Laramie cement plaster industry, by Slosson and 

Moodv; Tenth Annual Report of Univ. of Wvoming, pp. 1-17: 

ZULKOWSKI— Das Erharten des gypses; Thonindustrie, Vol. XXIII, 

pp. 1250-1252: 1899. 

240 GYPSUM. 


See also ante p. 193. 

AIKMAN — Manures and Manuring (London), pp. 462-464: 1894. 

BOSC — Royal Central Agricult. Soc. of France (vol. and page not 
found) ; sums up all information on the subject of gypsum as a 

BOUSSINGAULT— Rural Economy. 

BROWNE, D. J.— American Muck Book, pp. 68-75 : 1851 . 

BUEL — Farmer's Instructor. 

CHAPTAL — Chemistry Applied to Agriculture. 

CHUARD — Etude sur le Pl&tre; Journal de la Societe d'Agriculture, de 
la Suisse Romande, Vol. XXXII, No. 8, pp. 141-157 Lausanne: 

Fumure des Vignes avec le sulfate de chaux; Chronique 
agricole du Canton de Vaud, p. 75 : 1895, and in other numbers. 

DAVY — Agricultural Chemistry, about 1814. 

Gypsum as a fertilizer; Edinburgh Review, Vol. XXII, p. 279. 

FERTILIZERS — Value of gypsum in its action on insoluble potash in 
the soil, by Edw. Voorhees, p. 116, 1898. 

Importance of gypsum as manure; Quart. Review (London), 
Vol. XXIII, pp. 378, 379 : 1820. 

Facts and Observations respecting Canada and U. S., by 
Grece; (discusses the subject of gypsum). 

Sir. H. Davy on gypsum fertilizers; Edinburgh Review, Vol. 
XXII, p. 279 : 1814. 

GYPSUM AS A MANURE— Experiments of Mr. Ilarbe; Agric. Soc. of 
Eng., Vol. Ill, p. 234 : 1842. 

The Gardeners' Chronicle and Agricultural Gazette (London), 
p. 858, 1844 ; p. 785, 1841 ; pp. 387, 388 : 1864. 

Manures and the principles of Manuring, by Aikman (Lon- 
don) : 1894. 

HARRIS— Talks on Manures, p. 204 : 1878. 

JOHNSON, C. W. — An account of gypsum as a manure to the artificial 
grasses (prize essay) ; Proceedings of Roval Agricultural So- 
ciety of England, Vol. II : 1841. 

JOHNSTON— Manures, pp. 177, 178: 1895. 

Use of lime in Agriculture, pp. 204 f f : 1849. 

KING— The Soils, pp. 177, 178 : 1895. 

LIEBIG — Chemistry of Agriculture. 

MARVEL, IK— (Donald Mitchell), My Farm of Edgewood. 

MASSEY, W. F.— Crop Growing and Crop Feeding, July, 1901. 

PARKINSON — Practical Observations on Gypsum as a Manure. 

ROBERTS— The Fertility of the Land, p. 254 : 1897. 

RUFFIN, EDMUND— Calcareous Manures (first written in 1832) pp. 
147, 154 : 1852. 

SNYDER— The Chemistry of Soils and Fertilizers, p. 1(51: 1899. 

STEPHENS, HENRY— The Book of the Farm, Vol. II, pp. 423, 424: 

STOCKHARDT— The Familiar Exposition of the Chemistry of Agricul- 
ture, p. 226 : 1855. 


8T0RER— Chemistry of Agriculture, Vol. I, pp. 206, 216 : 1887. 
THIBAUT — Anwendung des Gypses als Btingen; Annales des Mines, 

series 3, Vol. VI, p. 193. 
TURNER— Elements of Chemistry. 

VIRGINIA — Resources of Southwest Virginia, by Bovd, p. 106. 
VOORHEES— Fertilizers, pp. 115, 116 : 1898. 
WILEY — Principles and Practice of Agricultural Analysis, Vol. II, pp. 

307,307: 1895. 
- WILSON— Rural Encyclopedia, Vol. II, article on Fertilizers: 1850. 




Absorption, tests of 176 

Adamant wall plaster 110 

Adhesion, tests of 178 

Alabaster, gypsum area. . .51, 56, 60, 66 

analyses of plaster 158 

analyses of rock 153 

history of 50 

mines and mills 68, 111 

Alabastlne 47, 50, 217 

Alabastlne Piaster Company 99, 102 

analyses of plaster. .159, 160 

analyses of rock 150 

Alpine Plaster Company 35 

Alnm plasters 213 

Ammonia retained by gypsum 198 

Analyses, chemical, of gypsum from 

Alabaster ! 153 

Aiabastine quarry 150 

Durr quarry 151 

English quarry 151 

Florida 145 

Grand Hapids Plaster Co. 151 

Grayling 154 

gypsite 38, 39, 40 

Hartz 143 

Hawaii 144 

Iowa 145 

Kansas 146 

Mt. Pleasant 90 

New South Wales 143 

New York 144 

Nova Scotia 144 

Ohio 145 

Philippines 143 

St. J gnace 153 

St. Marcos Island 143 

method of 149 

of plaster of Paris, 

from France 155 

Kansas 156 

Ohio 156 

Oklahoma 157 

Texas 157 

Wyoming 156 

from Winchell rej^rte 152 

Anhydrite, 84, 86, 68, 69, 90, 91, 97, 

140, 144 155- 

forming gypsum 185 

Lane's theory of origin. 185 

Animal origin of gypsum 184 

Apted, A. M 4 

Arkansas, gypsum in 29 

An tfres, gypsum 74 

Australia, gypsum 12 


Bailey, E. H. S. quoted, 39, 145, 149, 

154, 156, 157, 158 

Bayport, limestone 53, 56 

Beauregard plaster kiln 19 

Bibliography of gypsum 232 

Bigsby,J.J 8a 

Boiler incrustation 142 

Konsslngaulf '* experiments 200 

Brisson plaster kiln 18 

Bnlterworth, R. E 4T 


Calcining, machinery for 119 

progress in 130 

• methods io K ranee IT 

in Germany . . 20, 21 

temperatures of 124, 141 

California gypsum 34 

chemical compos- 
ition 147 

Canada gypsum 14 

chemical compos- 
ition 144 

Carboniferous salt sea in Michigan. 187 

Caspian sea 188 

Chalker, Wm. S 82 

Cbaptal, theory of gypsum as fertili- 
zer 197 

Chatelier, theory of set of plaster 136, 138 
effect temperature on 

gypsum 141 

Chemistry of gypsum (see Analyses) 140 

Chnard, Professor 194 

Church, M. V 8,47, ,V> 




Clark, James 42 

Cobb, M. A 90 

Cole, Emma 56 

Colorado gypsum 31 

chemical compos- 
ition 146 

Compression, tests of 176 

Cone-in -cone structure 100, 109 

Crayon, gypsum manufacture 205 

Crystallization 133 

Cummer, rotary calciner 126 

Cyprus gypsum 15 

Datns, F. B 158 

Dairy's theory of gypsum as fertilizer 201 

Dead Sea 185 

chemical composition . 186 

De Candolle, theory of gypsum as 

fertilizer 197 

Drainage of alabaster area 65 

Grand Rapids area 59 

Dumesnil plaster kiln 19 

Durr, mine and mill 49, 109 

analysis of rock 151 


Elerations in alabaster area 76 

Emery, stone mill 118 

England, gypsum in 11 

English, mine and mill 108 

analysis of plaster... 159 

of rock 151 


Fertilizer, gypsum used as 192 

Flbered plaster 213 

Fineness, tests 162 

Floor, blocks of plaster 220 

Florida, gypsum analysis 145 

France, gypsum in 16 

analyses 155 

method of calcining 17 


Ganging of plaster 163 

Geology and topography of Michigan 

gypsum 52 

Germany, gypsum in 20 

methods of calcin- 
ing 21 

Gllmore wires 164 

Glacial geology of Alabaster area. . 60 
of Grand Rapids 

area 56 

Glendon Dam gvpsum 69 

Godfrey, Freeman 45, 46. 47, 130 

Godfrey, mine and mill 104, 105 

Grand Rapids, deep wells at 92 

group 84 

gypsum area, geology 57 

history . 42 

topography 59 

Grand Rapids Plaster Co., 48, 107, 

108, 151 

Grand Rirer 59 

Grandrille, gypsum area, history. . . 40 
mines and 

mills 109 

Grayling, gypsum analysis 154 

Great Salt Lake 185 

Grece's observations on gypsum 196 

Gregory, W. M 1, 60, 112, 113 

Grimsley. theory of set of plaster.. . 136 
Gypsite, (gypsum earth) chemical 

analyses 38, 39, 146 

in Indian Territory 37 

Kansas 36 

Oklahoma 37 

Texas 38 

Wyoming 38 

microscopical structure 39 

origin of 40 

reference to 28, 29, 31, 32 

Gypstone 212 

Hanctin plaster kiln 18 

Harris's experiments on gypsum as 

fertilizer : 197 

Harmon City gypsum 75 

Hartz Mountains gypsum 20, 143 

Haworfh, Erasmus 83 

History of gypsum 5 

Michigan gypsum industry 42 

Houghton, Douglass 42, 43 

Horey, Wm 48 

Humphrey, R. L. 161, 162, 163, 180 

Hunt, T. Sterry, on origin of gypsum 183 

Huron County gypsum 77, 79 


India gypsum 12 

Indian Territory gypsite 37, 146 

Iowa gypsum 27, 145 

Italy gypsum 22 


Kausas, gypsum of 28 

chemical compos- 
ition of 146, 156 

gypsite 36 

used as fertilizer.... 202 

Kedzie,F. S 192 

Kettles, calcining 45, 119 

Keyes, Chas. R 53, 54, 55 

Keystone Dam gypsum 71 

Keystone Plaster Company 81 

Kilns, plaster 18 

Knight, Wilbur 38 

Lath 210 

Laud Piaster 43, 44, 47 



Land Plaster— Continued. Page 

references to use in 

Michigan 193 

Landrln theory of set of plaster, 136, 138 

Lane, Alfred C 1, 53, 54, 55, 56 

Lavoisier, on chemical composition 

of gypsum 140 

theory of set of plaster, 135, 138 

Lererett, Frank 1, 8 

Lleno, wall finish 217 

Lovelock, Nevada gypsum 33 

Lycoming Calcining Company 127 


Mackinac Lumber Company well — 81 
Manufacture, process of (see Tech- 

Marble, artificial 206 

Marignac 138, 139 

Maxrllle limestone 54, 56, 66, 71 

Hears, J.J 95 

Mediterranean Sea 187 

Metal Lath 210 

Method of chemical analyses of gyp- 
sum 149 

Michigan and Ohio Plaster Associa- 
tion : 8, 47 

Michigan Basin, its geological 

history 54 

Michigan Group of rocks 53. 56 

Microscopical Structure of gypsite. 39 

of plaster. . . 137 
Mills, gypsum in Michigan, 99, 102, 

105, 107, 108, 110, 111, 112 

Mineraloglcal properties of gypsum 3 
Mines, gypsum in Michigan, 99, 101, 

105, 107, 109, 111 

Nevada gypsum 33 

Mew Mexico gypsum 35 

New York gypsum 23, 144 

Normal Consistency of cement 163 

Nora Scotia gypsum 14, 144 


Ohio gypsum 25, 145, 156 

Oklahoma gypsum 29, 37, 146, 157 

Oregon gypsum 35 

Origin of* gypsite 40 

of gypsum 182 

in Ohio 26 

Paris 17 


Paints, gypsum 216 

Paleozoic formations in Alabaster 

area 66 

Paris gypsum 16 

Payen 136, 138, 141, 214 

Pennsylvania gypsum 26 

Physical Examination of gypsum 

plasters... 161 


Physical tests compared with chem- 
ical analyses 174 

Pittsburg Plate Glass Company test 

wells 95 

Plaster Creek 59 

Plaster of Paris 208 


155, 156, 157. 158, 159, 160 

Plate glass plaster 219 

Portland cement made from gypsum 222 

use of gypsum in . . 206 

Pottery moulds of plaster 218 

Powers gypsum mine and mill, 105, 

106, 160 

Prindle, Daniel 43 


Quantity, total of gypsum in Mich- 
igan 98 


Kabbltt's Back, gypsum area 82 

Ramdohr, plaster kiln 18 

Rathbone, Amos 46, 47 

Relief forms in Alabaster area 63 

Relief plaster work 219 

Retarders 129, 132 

Rifle Rirer 65 

Rominger, Dr. Carl 56, 69 

Rofflu'g experiments on gypsum as 

fertilizer 196 

Rumsey, James 43, 44, 46 

Sampling, method of 148 

Sand and its influence on plaster — 181 

Screens 129 

Sea water, chemical composition of 186 
Secondary gypsum deposits (see Gyp- 


Seleulte analyses 152 

Selinitlc lime 216 

Set of plaster 135 

Sherwln, R. S 183 

Shore forms, recent 64 

Silurian wells »7 

Sink Holes in Alabaster area 64, 70 

Smith k Bollard Plaster Co 50 

Solubility of gypsum 4 

South Dakota gypsum 36 

Specific gravity tests 79 

Spring water theory of origin of 

gypsite 41 

Statistics of gypsum 224 

of land plaster, 1X42- 

1870 47 

Stedman disintegrator 118 

St. Ignace gypsum deposits... .84), si, 153 
St. Martin's Island gypsum de- 
bits, 80.... 83 
Stockhardt's theory of gypsum as 

fertilizer 199 




Storer theory of gypsum as fertil izer 201 

Stneco 129 

Stordevant emery stone mill UN 

Sulphur Springs forming gypsum.. 182 

Sweden gypsum 22 

Switzerland gypsum 22 


Tables showing production of cal- 
cined plaster 226 

import* of gypsum 

into U. S 230 

land plaster in l\ S 225 
Michigan gypsum 

output 231 

tensile strength 

tests 168 

United States gyp- 
sum production by 

states \ 228 

United States gyp- 
sum production bv 

years 224, 229 

World's production 

of gypsum 227 

Tasmania gypsum 14 

Technology of gypsum and gyp&um 

plasters 115 

calcining methods 1 li) 

crushers 116 

in early Michigan mills 

44. 45, 4* 51 
in present Michigan 

mills 103, UK), HW llu 

Temperatures used in calcining plas- 
ter 124, 141 

Tensile strength of gypsum plasters, 105 

of lime plaster 177 

Terra alba 204 

Tests of wall plasters 161 

Texas gypsum 3<). 140 157 

Time of set 1«3 

Topography of Alabaster area 00 

Grand Rapids area. . oil 
recent shore forms Ala- 
baster 04 

relief forms Alabaster.. 03 

sink holes 04 

Trlppollte 21* 

Turner gypsum deposit 73 

Twining gypsum deposit 70 


Union Mills Plaster Company 40 

United States Gypsum Company. .1. 


7, 8, 24, 25, 28. 4s, 49. 51. 108, 111, 217 

United States gypsum deposits 23 

Uses of gypsum 204 

in England 11 

in India 13, 14 

Utah gypsum 35 


Van Wormer, L. experiments on 

gypsum of 199 

Fein deposition of gypsum 191 

Vicat needle 164 

Violette plaster kiln 18 

Virginia gypsum 26 


Weight tests 162 

Well borings, a study of 84 

Well deep, records, Alma 90 

Bay City 86 

Beyrich brew- 
ery 95 

Butterworth 94 

Corunaa 89 

East Sagi naw ... 87 

Freemont Co. . . 88 

Godfrey 92 

Grayling 85 

Indian Mill 

Creek 94 

Kawkawlin 87 

Lvous 93 

Midland 89 

Mt. Pleasant... 90 

< >wosso N9 

Pittsburg Plate 

Glass Co 95 

Powers and Mar- 
tin 93 

Sanford 88 

Scr'ibner 93 

South Bay City. 86 

South Saginaw.. 87 

State salt well.. 93 

St. Ignuce 81 

Windsor 94 

Weller, Stuart r>4. o.">, 56 

White, Ueo. H 46, 47 

White gypsum mill Ill 

Wliitteniore test holr 75 

Wilder, Frank A :*, 22 

Williams If. S 52 

Wiurhell, Alexander 69. 7.\ »1. 113 

Wyoming gypsum «'J2, 146, 156 
















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